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The SEGA MKIII 256M Myth flash cart from NeoFlash has been available for a little while now. You can buy it from ic2005 for about $100 with a 256 Mbit flash cart. The most notable difference to other flash carts out is that it has the YM2413 FM chip built in. So what's new? Mic and I just released v1.0 of the replacement menu that allows people with a Neo2-SD or Neo2-Pro in their MKIII Myth to run games from the SD card. You can also play VGM files from the SD card (PSG-only VGM files currently - FM will be added at some point).

Info on the MKIII 256M Myth cart
Neo SEGA4 Menu v1.0
MKIII 256M Myth at ic2005
Neo2-SD flash cart at ic2005

I'd almost forgotten about this flash cart.

How does it compare to the Master Everdrive? The number one gripe I have with the everdrive is the way ROM images are copied to EEPROM before playing. This makes writing debugging tools with runtime breakpoint support virtually impossible. Also, I get irrationally nervous about wear levelling. I seem to recall reading somewhere that the Myth flash cart runs from an SRAM. Is that the case?

One great thing about the everdrive the USB send tool runs in Linux (via Mono). Are there any tools for the Myth cart that run on Linux or would I have to write my own?

Thanks muchly!

There is an open source client that works for the MD Myth, which should also work for the MKIII Myth... I need to check that out. The open source client is designed around *nix platforms, and I've used it in Xubuntu. I won't say it works for sure until I get a chance to try it. The official client runs under Windows.

The Myth cart doesn't have a USB port, it comes with a SlimLoader IV instead. The SLIV is a USB interface that allows programming GBA flash carts over USB. The Myth series of flash carts are really adapters that allow GBA flash carts to be used on other consoles, namely the SMS, MD, SNES, and N64. The menus currently just support NeoFlash GBA flash carts (for obvious reasons), but given the open source nature of them, other GBA carts could be supported.

The MKIII Myth comes with the SlimLoader IV, a 256 Mbit NeoFlash GBA flash cart for storage, and the MKIII Myth itself. To load from an SD card, you would also need a Neo2-SD or Neo2-Pro flash cart, both of which have an SD interface. It does NOT work with the Neo3-SD card because the Neo3 doesn't have game flash or psram.

Which brings me to another point on your post - the MKIII Myth runs the games from the game flash of the GBA flash cart... on the Neo2-SD/Neo2-Pro, in addition to the SD interface, they come with psram. The psram can be switched into place instead of the game flash. So the MKIII Myth menu loads the game from the SD card, writes it to the psram, then runs it as if it were in flash. The MKIII Myth supports games up to 16 Mbits in size, though the largest games made are GG ports, which are 8 Mbits. Guess they wanted to be sure if anything new (homebrew) came out at more than 8 Mbits, it would still work.

The MKIII Myth has the FM chip inside. If you follow the first link in my post, you'll see pictures. There are AV inputs on the cart as well as AV outputs. You run the AV from the SMS to the input on the cart. The MKIII Myth then mixes the SMS audio with the FM chip inside, then outputs the mixed audio and the video (unchanged) to the AV output. You run the AV output to the TV.

So there's no DIRECT control by a PC for live debugging, but everything but the menu can be run from the SD card. So once you write the menu once, everything else is run in ram from the SD card. That's also pretty fast for checking games... copy to the SD from the PC and run on the SMS from SD. You also never have to worry about bad sectors in the flash since it runs from ram. You CAN run games from the flash if you want to, but I don't see why you would if you can run from SD. :)

The menu is written using C and assembly via sdcc, and the source can be found on the google code page set up for all the Myth menus, found here:
http://code.google.com/p/neo-myth-menu/

The open source client can also be found on google code pages at:
http://code.google.com/p/neo-myth-programmer/

I do my programming in Xubuntu, but normally use the Windows client in Windows XP on my old laptop since it supports all the Myth carts. The open source client needs more work in regards to supporting the other carts.

The MKIII Myth also has support for one cheat in hardware (not supported by the SD menu yet, but will be soon). This allows you to force the value at any address (normally ram). We will also support applying patches to the rom as it's loaded like we do on the other consoles. That's the nice thing about an open source menu - you can get several guys helping to add features. Mic and I did the main parts, and conle will be working on the cheats/patches. Anyone who wishes to help is welcome, hence the google code pages.

So - basic comparison:

Master Everdrive:
About $80 for a bare board, but comes with a USB port and the SD interface.
Copies games from SD card to the flash; supports up to 8 Mbits.
Has 32 KBytes of FRAM for saves.
Menu currently only supports plain SD cards up to 2 GB in FAT16 format, but it can be updated to do better.

MKIII Myth:
About $100 with case, but just a 256 Mbit flash cart with no SD interface. About $160 with a Neo2-SD flash cart giving the SD card interface.
No USB port, but comes with SlimLoader IV USB interface to program flash carts over USB.
Games can be run from flash, or (if you have a Neo2-SD or Neo2-Pro) from SD card. The menu currently supports nearly all SD and SDHC cards in FAT16 or FAT32 format, for up to 32 GB of space. Kind of overkill seeing as all SMS games and VGM music won't fill more than a few MBytes. :)
Has 256 KBytes of save ram.
Games can be up to 16 Mbits on either flash or psram from SD card.
Has YM2413 FM chip with on cart audio mixing.
Has one hardware cheat that can be switched on or off on the fly by a switch on the Myth.

Of note: The Master Everdrive is faster loading from SD card since the SD interface is built into it and supported through the hardware. The Myth uses the CPU to handle the SD interface from the Neo2-SD/Neo2-Pro, so it's not as fast. It's not a big deal in my opinion - the games are too small to really give big load times, and we're working on improving the load speed in the Myth menu.

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The Myth uses the CPU to handle the SD interface from the Neo2-SD/Neo2-Pro, so it's not as fast. It's not a big deal at my opinion - the games are too small to really give big load times, and we're working on improving the load speed in the Myth menu.

I can fill in some details here for those of you familiar with the SD/MMC standard and the Master System memory map:

When enabled, the Neo2 cart's SD interface is exposed to the CPU as a number of memory locations in Frame 1 (0x4000-0x7FFF) that you read from. We use native 4-bit mode for communicating with the SD card since SPI mode would be horribly slow without any kind of hardware assistance.

The Neo2 cart's PSRAM that we load games / songs to from the SD card also maps into Frame 1, so you cannot access PSRAM and the SD interface at the same time. Hence it's not possible to read data directly from the SD card into PSRAM. Instead we have to read data into the SMS's 8 kB WRAM, enable PSRAM and copy the data from WRAM to PSRAM.

The fastest way of doing this would be to use the multi-sector read functionality of SD cards where you only send a single start/stop command for a number of sectors (e.g. an entire cluster). But there's only so much WRAM available, and a lot of other stuff has to fit in there as well, so reading more than 2 or 3 sectors in one go would be impractical.
The current version of the menu only does single-sector reads, which is the slowest method (reading speed is currently about 25 kB/s).

It'd be obviously faster if this copying was done without every byte going through the Z80 and particularly via the system RAM (so it's all copied twice); 25KB/s is not bad throughput for the SMS but waiting 41s for a 1MB game is not ideal. Doing two or three sectors at a time probably wouldn't make much difference, I expect. I don't think any currently released cart supports fast transfers outside the Z80 bus. Support for zipped ROMs would also be an interesting feature if it came out faster than an uncompressed copy.

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Doing two or three sectors at a time probably wouldn't make much difference, I expect.

I did a quick test with reading 2 sectors at a time a couple of days ago, and got something like a 20% speedup. But then you need to handle the special case of a read that could cross a cluster boundary for ROMs that have the 512-byte copier header.

Quote

Support for zipped ROMs would also be an interesting feature if it came out faster than an uncompressed copy.

It should certainly be possible to do. I implemented support for zipped ROMs in the menu for the SNES Myth. But the inflate algorithm would probably be very slow on the SMS because for every byte you read or write you'd have to check if you've crossed a 16 kB frame boundary.

Chilly Willy wrote

The Myth cart doesn't have a USB port, it comes with a SlimLoader IV instead.

That's unfortunate. I'll be sticking with the everdrive for the time being. I should probably have a go at building my own. Curse my mediocre electronics skills!

mic_ wrote

Quote

Doing two or three sectors at a time probably wouldn't make much difference, I expect.

I did a quick test with reading 2 sectors at a time a couple of days ago, and got something like a 20% speedup. But then you need to handle the special case of a read that could cross a cluster boundary for ROMs that have the 512-byte copier header.

Well, you don't HAVE to read multiple sectors into ram, then copy to psram. Just copy after every sector - the slow down with single sector reads is the command sequence you have to go through for EVERY sector. Start the multi-sector read, then for each sector, read it in, copy to psram, then loop. The overhead for copying to psram is the same no matter what, and flipping between the psram and SD interface is a matter of only writing one Myth register and the frame page number. It means we'd need a little more integration between the psram copy routine and the SD read routine, which are currently completely separated.

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Quote

Support for zipped ROMs would also be an interesting feature if it came out faster than an uncompressed copy.

It should certainly be possible to do. I implemented support for zipped ROMs in the menu for the SNES Myth. But the inflate algorithm would probably be very slow on the SMS because for every byte you read or write you'd have to check if you've crossed a 16 kB frame boundary.

Given how slow unzipping is on a stock 68000, I imagine instead of waiting 41 seconds for a 1MB file to load, you'd wait 4 minutes for a 1MB file to decompress. :D

You'd need to use a compression format that was VERY fast decompressing or it's not worth it.

Just to make something clear which is not by everything I've read in this thread so far...

1. Master Everdrive has 32k fram for saves BUT it saves this fram's image into 32k files in the SD, so every game has its own dedicated 32k for saves. It loads it and saves it as soon as you load or exit the corresponding game's rom.
The Myth has 256k saving ram for all games.... period. If its full you have to delete to make space.

2. The Master Everdrive also uses the console's cpu for SD usage. So the claim that the Myth uses the console's cpu for accessing the SD and thats the reason its slower on that compared to the Master Everdrive is not valid.

ps
The Yamaha chip on the Myth is very cool. I hope it sounds as it should on that one.

gtsamour wrote

Just to make something clear which is not by everything I've read in this thread so far...

1. Master Everdrive has 32k fram for saves BUT it saves this fram's image into 32k files in the SD, so every game has its own dedicated 32k for saves. It loads it and saves it as soon as you load or exit the corresponding game's rom.
The Myth has 256k saving ram for all games.... period. If its full you have to delete to make space.

Currently, yes. Eventually the menu for the Myth will handle saves the same way. If you CURRENTLY want to save/restore the save ram, you have to use the SlimLoader IV and the PC client to do so.

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2. The Master Everdrive also uses the console's cpu for SD usage. So the claim that the Myth uses the console's cpu for accessing the SD and thats the reason its slower on that compared to the Master Everdrive is not valid.

Not quite true - the Everdrive uses SPI mode with a serial interface in the Everdrive hardware to run as fast as the CPU can handle. The Myth uses SDIO mode with the CPU handling each cycle, where the command phase is sent a bit at a time and the data phase received four bits at a time.

I keep hoping NeoFlash makes a new GBA flash cart that has more hardware in it to help speed transfers from SD (or any other card) to the psram. If they DO make one, we'll add support for it to the menu for instant speed boost.

In any case, there are things we can do to make the MKIII Myth load faster, so it'll speed up as we improve that part of the menu. The first MD Myth menu only loaded at about 25 KB/sec as well, and it's now like about 120 KB/sec. I don't think we'll match that on a Z80, but we'll certainly do BETTER than it is currently.

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ps
The Yamaha chip on the Myth is very cool. I hope it sounds as it should on that one.

Sounds good to me, but I'm hardly an audiophile. :D

Chilly Willy wrote

Sounds good to me, but I'm hardly an audiophile. :D

Me neither, but I can make out when something sounds good or not.
Don't need to be an audiophile to know distortion when you hear it.

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The first MD Myth menu only loaded at about 25 KB/sec as well, and it's now like about 120 KB/sec. I don't think we'll match that on a Z80, but we'll certainly do BETTER than it is currently.

The maximum speed possible with the current HW/FW is something like 51 kB/s, i.e. roughly twice of what we have now. I'm currently working on implementing multi sector reading, which should bring the speed closer to the maximum.

Here is a video of the menu in action on a PAL Master System (model 1): http://www.youtube.com/watch?v=qfKKSuZSZv8

The SD card reading speed has been increased to about 35 kB/s. It should be possible to increase it even further, especially for files with little or no fragmentation.

Silly question, will it work in a Japanese Master System, with the use of an adapter? Not that there's much point, just wondering is all.

Also, not being familiar with these products, is the following correct:

- The stock package includes a 256M myth cart which is where roms are stored. This is achieved by plugging it into the included USB loader and transferring via PC?

- To run roms from an SD card, you need to buy this: http://www.ic2005.com/shop/product.php?productid=119&cat=3&page=1

^ Am guessing the SD card slots into the top of the Neo2 Pro?

Is there a package deal available? $99 for the MK III and another $89 for the Neo2 plus whatever shipping comes to is a little steep.

Frank_fjs wrote

Silly question, will it work in a Japanese Master System, with the use of an adapter? Not that there's much point, just wondering is all.

I have no idea, but I don't see why it wouldn't work.

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Also, not being familiar with these products, is the following correct:

- The stock package includes a 256M myth cart which is where roms are stored. This is achieved by plugging it into the included USB loader and transferring via PC?

256Mbit GBA flash cart, otherwise, yes, that is correct.

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- To run roms from an SD card, you need to buy this: http://www.ic2005.com/shop/product.php?productid=119&cat=3&page=1

^ Am guessing the SD card slots into the top of the Neo2 Pro?

That or the cheaper Neo2-SD. The Neo2-Pro is mainly for people who have (or will have) the N64 Myth since is has more flash/psram for the larger N64 games. The SMS has nothing so big that the Neo2-SD wouldn't be sufficient.

There is also an even cheaper Neo2-Twin cart, but I'm not sure if that works with it or not. I only have the Neo2-SD and Neo2-Pro for testing. I CAN say that the Neo3-SD/TF will NOT work since it doesn't have any psram in the GBA flash cart, or game flash for that matter. The Neo3-SD will only work on Myths with PSRAM inside the Myth itself, like the MD Myth or the SNES Myth.

Quote

Is there a package deal available? $99 for the MK III and another $89 for the Neo2 plus whatever shipping comes to is a little steep.

There's no bundle deal, but like I mentioned above, there is a cheaper alternative to the Neo2-Pro, which is a bit expensive if you only plan on having the MKIII Myth. It's $20 less.

http://www.ic2005.com/shop/product.php?productid=41&cat=0&featured=Y

Thanks for the info Chilly Willy. :)

Wish they all just used a standard SD interface, built into the flash cart itself. A lot cheaper and more convenient this way, and a lot less confusing!

I'm still not sure which way to go, between the Myth or the Everdrive. I only want to play games and don't require any homebrew/software development tools. The FM chip of the Myth is super cool but already owning a Japanese MS not that important to me. I guess the one with the easiest transferring and loading of roms would suit me better, and the Everdrive looks to be the way to go and is a little bit cheaper.

Frank_fjs wrote

Thanks for the info Chilly Willy. :)

Wish they all just used a standard SD interface, built into the flash cart itself. A lot cheaper and more convenient this way, and a lot less confusing!

I'm still not sure which way to go, between the Myth or the Everdrive. I only want to play games and don't require any homebrew/software development tools. The FM chip of the Myth is super cool but already owning a Japanese MS not that important to me. I guess the one with the easiest transferring and loading of roms would suit me better, and the Everdrive looks to be the way to go and is a little bit cheaper.

Yeah, if you don't need the extras, the Everdrive family is usually the best buy for the money. The Myth line is more expensive, but some people want/need to extras that come with them. The Myth stuff can be a little confusing as well, but it has a pretty good forum that's usually helpful in getting the info you need.

One thing I'm looking forward to is the Everdrive for the PCE coming next year. The current flash cards for the PCE (including the NeoFlash one) aren't all that good.

Frank_fjs wrote

Silly question, will it work in a Japanese Master System, with the use of an adapter? Not that there's much point, just wondering is all.

I don't know about the myth flash cart, but the Everdrive works with a Japanese Master System with a Tototek converter with full FM support. Check out my post....http://www.smspower.org/forums/viewtopic.php?t=12915

Great info, thanks for sharing Lan Di. :)

I do have the Tototek converter and a Japanese MS so I'm set.

One thing that I just thought of re the Myth cart, I hook my console up via RGB SCART and it seems the Myth cart limits you to composite video only. I'd probably live with that if I didn't have a Japanese MD and wanted to experience some FM goodness, but then again for the cost of the Myth cart I'd rather just get the real thing, i.e. a Japanese MS.

Frank_fjs wrote

Great info, thanks for sharing Lan Di. :)

I do have the Tototek converter and a Japanese MS so I'm set.

One thing that I just thought of re the Myth cart, I hook my console up via RGB SCART and it seems the Myth cart limits you to composite video only. I'd probably live with that if I didn't have a Japanese MD and wanted to experience some FM goodness, but then again for the cost of the Myth cart I'd rather just get the real thing, i.e. a Japanese MS.

Actually, you only need to pass the audio through the Myth. The video is only there to make cable hookup easier - one AV cable to the Myth, and one rca stereo cable from the Myth to the TV. The video is neither needed by the Myth, nor altered, merely passed through.

Chilly Willy wrote

Actually, you only need to pass the audio through the Myth. The video is only there to make cable hookup easier - one AV cable to the Myth, and one rca stereo cable from the Myth to the TV. The video is neither needed by the Myth, nor altered, merely passed through.

This is good to know and be clarified. I was always put off by the idea of having to connect a SMS with RCA cables.

Bock wrote

Chilly Willy wrote

Actually, you only need to pass the audio through the Myth. The video is only there to make cable hookup easier - one AV cable to the Myth, and one rca stereo cable from the Myth to the TV. The video is neither needed by the Myth, nor altered, merely passed through.

This is good to know and be clarified. I was always put off by the idea of having to connect a SMS with RCA cables.

+1, this should be mentioned in the product details as well I think.

I ordered a Master Everdrive a couple of weeks ago, but I've got one of viletim's FM boards installed on my Master System so I don't feel like I'd be missing out on much stuff I'm interested in. Plus I'd rather use SD than a GBA flashcart. Which is very creative.

Frank_fjs wrote

Bock wrote

Chilly Willy wrote

Actually, you only need to pass the audio through the Myth. The video is only there to make cable hookup easier - one AV cable to the Myth, and one rca stereo cable from the Myth to the TV. The video is neither needed by the Myth, nor altered, merely passed through.

This is good to know and be clarified. I was always put off by the idea of having to connect a SMS with RCA cables.

+1, this should be mentioned in the product details as well I think.

We occasionally make suggestions about the product details on the forum. I've already had Dr.neo change the MD Myth combo product details. :)

Author	Message
Chilly Willy Joined: 23 Jan 2011 Posts: 65 Location: The Land of Enchantment	SEGA MKIII 256M Myth flash cart Posted: Sun Oct 16, 2011 7:36 pm
	The SEGA MKIII 256M Myth flash cart from NeoFlash has been available for a little while now. You can buy it from ic2005 for about $100 with a 256 Mbit flash cart. The most notable difference to other flash carts out is that it has the YM2413 FM chip built in. So what's new? Mic and I just released v1.0 of the replacement menu that allows people with a Neo2-SD or Neo2-Pro in their MKIII Myth to run games from the SD card. You can also play VGM files from the SD card (PSG-only VGM files currently - FM will be added at some point). Info on the MKIII 256M Myth cart Neo SEGA4 Menu v1.0 MKIII 256M Myth at ic2005 Neo2-SD flash cart at ic2005

Glitch Joined: 16 Dec 2008 Posts: 38 Location: UK	Posted: Mon Oct 17, 2011 6:25 pm
Glitch Joined: 16 Dec 2008 Posts: 38 Location: UK	I'd almost forgotten about this flash cart. How does it compare to the Master Everdrive? The number one gripe I have with the everdrive is the way ROM images are copied to EEPROM before playing. This makes writing debugging tools with runtime breakpoint support virtually impossible. Also, I get irrationally nervous about wear levelling. I seem to recall reading somewhere that the Myth flash cart runs from an SRAM. Is that the case? One great thing about the everdrive the USB send tool runs in Linux (via Mono). Are there any tools for the Myth cart that run on Linux or would I have to write my own? Thanks muchly!

Chilly Willy Joined: 23 Jan 2011 Posts: 65 Location: The Land of Enchantment	Posted: Tue Oct 18, 2011 4:16 am
	There is an open source client that works for the MD Myth, which should also work for the MKIII Myth... I need to check that out. The open source client is designed around *nix platforms, and I've used it in Xubuntu. I won't say it works for sure until I get a chance to try it. The official client runs under Windows. The Myth cart doesn't have a USB port, it comes with a SlimLoader IV instead. The SLIV is a USB interface that allows programming GBA flash carts over USB. The Myth series of flash carts are really adapters that allow GBA flash carts to be used on other consoles, namely the SMS, MD, SNES, and N64. The menus currently just support NeoFlash GBA flash carts (for obvious reasons), but given the open source nature of them, other GBA carts could be supported. The MKIII Myth comes with the SlimLoader IV, a 256 Mbit NeoFlash GBA flash cart for storage, and the MKIII Myth itself. To load from an SD card, you would also need a Neo2-SD or Neo2-Pro flash cart, both of which have an SD interface. It does NOT work with the Neo3-SD card because the Neo3 doesn't have game flash or psram. Which brings me to another point on your post - the MKIII Myth runs the games from the game flash of the GBA flash cart... on the Neo2-SD/Neo2-Pro, in addition to the SD interface, they come with psram. The psram can be switched into place instead of the game flash. So the MKIII Myth menu loads the game from the SD card, writes it to the psram, then runs it as if it were in flash. The MKIII Myth supports games up to 16 Mbits in size, though the largest games made are GG ports, which are 8 Mbits. Guess they wanted to be sure if anything new (homebrew) came out at more than 8 Mbits, it would still work. The MKIII Myth has the FM chip inside. If you follow the first link in my post, you'll see pictures. There are AV inputs on the cart as well as AV outputs. You run the AV from the SMS to the input on the cart. The MKIII Myth then mixes the SMS audio with the FM chip inside, then outputs the mixed audio and the video (unchanged) to the AV output. You run the AV output to the TV. So there's no DIRECT control by a PC for live debugging, but everything but the menu can be run from the SD card. So once you write the menu once, everything else is run in ram from the SD card. That's also pretty fast for checking games... copy to the SD from the PC and run on the SMS from SD. You also never have to worry about bad sectors in the flash since it runs from ram. You CAN run games from the flash if you want to, but I don't see why you would if you can run from SD. :) The menu is written using C and assembly via sdcc, and the source can be found on the google code page set up for all the Myth menus, found here: http://code.google.com/p/neo-myth-menu/ The open source client can also be found on google code pages at: http://code.google.com/p/neo-myth-programmer/ I do my programming in Xubuntu, but normally use the Windows client in Windows XP on my old laptop since it supports all the Myth carts. The open source client needs more work in regards to supporting the other carts. The MKIII Myth also has support for one cheat in hardware (not supported by the SD menu yet, but will be soon). This allows you to force the value at any address (normally ram). We will also support applying patches to the rom as it's loaded like we do on the other consoles. That's the nice thing about an open source menu - you can get several guys helping to add features. Mic and I did the main parts, and conle will be working on the cheats/patches. Anyone who wishes to help is welcome, hence the google code pages. So - basic comparison: Master Everdrive: About $80 for a bare board, but comes with a USB port and the SD interface. Copies games from SD card to the flash; supports up to 8 Mbits. Has 32 KBytes of FRAM for saves. Menu currently only supports plain SD cards up to 2 GB in FAT16 format, but it can be updated to do better. MKIII Myth: About $100 with case, but just a 256 Mbit flash cart with no SD interface. About $160 with a Neo2-SD flash cart giving the SD card interface. No USB port, but comes with SlimLoader IV USB interface to program flash carts over USB. Games can be run from flash, or (if you have a Neo2-SD or Neo2-Pro) from SD card. The menu currently supports nearly all SD and SDHC cards in FAT16 or FAT32 format, for up to 32 GB of space. Kind of overkill seeing as all SMS games and VGM music won't fill more than a few MBytes. :) Has 256 KBytes of save ram. Games can be up to 16 Mbits on either flash or psram from SD card. Has YM2413 FM chip with on cart audio mixing. Has one hardware cheat that can be switched on or off on the fly by a switch on the Myth. Of note: The Master Everdrive is faster loading from SD card since the SD interface is built into it and supported through the hardware. The Myth uses the CPU to handle the SD interface from the Neo2-SD/Neo2-Pro, so it's not as fast. It's not a big deal in my opinion - the games are too small to really give big load times, and we're working on improving the load speed in the Myth menu.

mic_ Joined: 27 May 2008 Posts: 161	Posted: Tue Oct 18, 2011 3:23 pm
mic_ Joined: 27 May 2008 Posts: 161	Quote The Myth uses the CPU to handle the SD interface from the Neo2-SD/Neo2-Pro, so it's not as fast. It's not a big deal at my opinion - the games are too small to really give big load times, and we're working on improving the load speed in the Myth menu. I can fill in some details here for those of you familiar with the SD/MMC standard and the Master System memory map: When enabled, the Neo2 cart's SD interface is exposed to the CPU as a number of memory locations in Frame 1 (0x4000-0x7FFF) that you read from. We use native 4-bit mode for communicating with the SD card since SPI mode would be horribly slow without any kind of hardware assistance. The Neo2 cart's PSRAM that we load games / songs to from the SD card also maps into Frame 1, so you cannot access PSRAM and the SD interface at the same time. Hence it's not possible to read data directly from the SD card into PSRAM. Instead we have to read data into the SMS's 8 kB WRAM, enable PSRAM and copy the data from WRAM to PSRAM. The fastest way of doing this would be to use the multi-sector read functionality of SD cards where you only send a single start/stop command for a number of sectors (e.g. an entire cluster). But there's only so much WRAM available, and a lot of other stuff has to fit in there as well, so reading more than 2 or 3 sectors in one go would be impractical. The current version of the menu only does single-sector reads, which is the slowest method (reading speed is currently about 25 kB/s).

Maxim Site Admin Joined: 19 Oct 1999 Posts: 14752 Location: London	Posted: Tue Oct 18, 2011 5:04 pm
	It'd be obviously faster if this copying was done without every byte going through the Z80 and particularly via the system RAM (so it's all copied twice); 25KB/s is not bad throughput for the SMS but waiting 41s for a 1MB game is not ideal. Doing two or three sectors at a time probably wouldn't make much difference, I expect. I don't think any currently released cart supports fast transfers outside the Z80 bus. Support for zipped ROMs would also be an interesting feature if it came out faster than an uncompressed copy.

mic_ Joined: 27 May 2008 Posts: 161	Posted: Tue Oct 18, 2011 6:07 pm
mic_ Joined: 27 May 2008 Posts: 161	Quote Doing two or three sectors at a time probably wouldn't make much difference, I expect. I did a quick test with reading 2 sectors at a time a couple of days ago, and got something like a 20% speedup. But then you need to handle the special case of a read that could cross a cluster boundary for ROMs that have the 512-byte copier header. Quote Support for zipped ROMs would also be an interesting feature if it came out faster than an uncompressed copy. It should certainly be possible to do. I implemented support for zipped ROMs in the menu for the SNES Myth. But the inflate algorithm would probably be very slow on the SMS because for every byte you read or write you'd have to check if you've crossed a 16 kB frame boundary.

Glitch Joined: 16 Dec 2008 Posts: 38 Location: UK	Posted: Tue Oct 18, 2011 6:16 pm
Glitch Joined: 16 Dec 2008 Posts: 38 Location: UK	Chilly Willy wrote The Myth cart doesn't have a USB port, it comes with a SlimLoader IV instead. That's unfortunate. I'll be sticking with the everdrive for the time being. I should probably have a go at building my own. Curse my mediocre electronics skills!

Chilly Willy Joined: 23 Jan 2011 Posts: 65 Location: The Land of Enchantment	Posted: Tue Oct 18, 2011 10:59 pm
	mic_ wrote Quote Doing two or three sectors at a time probably wouldn't make much difference, I expect. I did a quick test with reading 2 sectors at a time a couple of days ago, and got something like a 20% speedup. But then you need to handle the special case of a read that could cross a cluster boundary for ROMs that have the 512-byte copier header. Well, you don't HAVE to read multiple sectors into ram, then copy to psram. Just copy after every sector - the slow down with single sector reads is the command sequence you have to go through for EVERY sector. Start the multi-sector read, then for each sector, read it in, copy to psram, then loop. The overhead for copying to psram is the same no matter what, and flipping between the psram and SD interface is a matter of only writing one Myth register and the frame page number. It means we'd need a little more integration between the psram copy routine and the SD read routine, which are currently completely separated. Quote Quote Support for zipped ROMs would also be an interesting feature if it came out faster than an uncompressed copy. It should certainly be possible to do. I implemented support for zipped ROMs in the menu for the SNES Myth. But the inflate algorithm would probably be very slow on the SMS because for every byte you read or write you'd have to check if you've crossed a 16 kB frame boundary. Given how slow unzipping is on a stock 68000, I imagine instead of waiting 41 seconds for a 1MB file to load, you'd wait 4 minutes for a 1MB file to decompress. :D You'd need to use a compression format that was VERY fast decompressing or it's not worth it.

gtsamour Joined: 13 Oct 2011 Posts: 4	Posted: Wed Oct 19, 2011 7:10 am
gtsamour Joined: 13 Oct 2011 Posts: 4	Just to make something clear which is not by everything I've read in this thread so far... 1. Master Everdrive has 32k fram for saves BUT it saves this fram's image into 32k files in the SD, so every game has its own dedicated 32k for saves. It loads it and saves it as soon as you load or exit the corresponding game's rom. The Myth has 256k saving ram for all games.... period. If its full you have to delete to make space. 2. The Master Everdrive also uses the console's cpu for SD usage. So the claim that the Myth uses the console's cpu for accessing the SD and thats the reason its slower on that compared to the Master Everdrive is not valid. ps The Yamaha chip on the Myth is very cool. I hope it sounds as it should on that one.

Chilly Willy Joined: 23 Jan 2011 Posts: 65 Location: The Land of Enchantment	Posted: Wed Oct 19, 2011 11:21 pm
	gtsamour wrote Just to make something clear which is not by everything I've read in this thread so far... 1. Master Everdrive has 32k fram for saves BUT it saves this fram's image into 32k files in the SD, so every game has its own dedicated 32k for saves. It loads it and saves it as soon as you load or exit the corresponding game's rom. The Myth has 256k saving ram for all games.... period. If its full you have to delete to make space. Currently, yes. Eventually the menu for the Myth will handle saves the same way. If you CURRENTLY want to save/restore the save ram, you have to use the SlimLoader IV and the PC client to do so. Quote 2. The Master Everdrive also uses the console's cpu for SD usage. So the claim that the Myth uses the console's cpu for accessing the SD and thats the reason its slower on that compared to the Master Everdrive is not valid. Not quite true - the Everdrive uses SPI mode with a serial interface in the Everdrive hardware to run as fast as the CPU can handle. The Myth uses SDIO mode with the CPU handling each cycle, where the command phase is sent a bit at a time and the data phase received four bits at a time. I keep hoping NeoFlash makes a new GBA flash cart that has more hardware in it to help speed transfers from SD (or any other card) to the psram. If they DO make one, we'll add support for it to the menu for instant speed boost. In any case, there are things we can do to make the MKIII Myth load faster, so it'll speed up as we improve that part of the menu. The first MD Myth menu only loaded at about 25 KB/sec as well, and it's now like about 120 KB/sec. I don't think we'll match that on a Z80, but we'll certainly do BETTER than it is currently. Quote ps The Yamaha chip on the Myth is very cool. I hope it sounds as it should on that one. Sounds good to me, but I'm hardly an audiophile. :D

gtsamour Joined: 13 Oct 2011 Posts: 4	Posted: Thu Oct 20, 2011 4:21 am
gtsamour Joined: 13 Oct 2011 Posts: 4	Chilly Willy wrote Sounds good to me, but I'm hardly an audiophile. :D Me neither, but I can make out when something sounds good or not. Don't need to be an audiophile to know distortion when you hear it.

mic_ Joined: 27 May 2008 Posts: 161	Posted: Thu Oct 20, 2011 2:34 pm
mic_ Joined: 27 May 2008 Posts: 161	Quote The first MD Myth menu only loaded at about 25 KB/sec as well, and it's now like about 120 KB/sec. I don't think we'll match that on a Z80, but we'll certainly do BETTER than it is currently. The maximum speed possible with the current HW/FW is something like 51 kB/s, i.e. roughly twice of what we have now. I'm currently working on implementing multi sector reading, which should bring the speed closer to the maximum.

mic_ Joined: 27 May 2008 Posts: 161	Posted: Fri Oct 21, 2011 9:52 am
mic_ Joined: 27 May 2008 Posts: 161	Here is a video of the menu in action on a PAL Master System (model 1): http://www.youtube.com/watch?v=qfKKSuZSZv8 The SD card reading speed has been increased to about 35 kB/s. It should be possible to increase it even further, especially for files with little or no fragmentation.

Frank_fjs Joined: 19 Aug 2011 Posts: 115 Location: Australia	Posted: Fri Oct 21, 2011 12:27 pm
	Silly question, will it work in a Japanese Master System, with the use of an adapter? Not that there's much point, just wondering is all. Also, not being familiar with these products, is the following correct: - The stock package includes a 256M myth cart which is where roms are stored. This is achieved by plugging it into the included USB loader and transferring via PC? - To run roms from an SD card, you need to buy this: http://www.ic2005.com/shop/product.php?productid=119&cat=3&page=1 ^ Am guessing the SD card slots into the top of the Neo2 Pro? Is there a package deal available? $99 for the MK III and another $89 for the Neo2 plus whatever shipping comes to is a little steep.

Chilly Willy Joined: 23 Jan 2011 Posts: 65 Location: The Land of Enchantment	Posted: Fri Oct 21, 2011 5:56 pm
	Frank_fjs wrote Silly question, will it work in a Japanese Master System, with the use of an adapter? Not that there's much point, just wondering is all. I have no idea, but I don't see why it wouldn't work. Quote Also, not being familiar with these products, is the following correct: - The stock package includes a 256M myth cart which is where roms are stored. This is achieved by plugging it into the included USB loader and transferring via PC? 256Mbit GBA flash cart, otherwise, yes, that is correct. Quote - To run roms from an SD card, you need to buy this: http://www.ic2005.com/shop/product.php?productid=119&cat=3&page=1 ^ Am guessing the SD card slots into the top of the Neo2 Pro? That or the cheaper Neo2-SD. The Neo2-Pro is mainly for people who have (or will have) the N64 Myth since is has more flash/psram for the larger N64 games. The SMS has nothing so big that the Neo2-SD wouldn't be sufficient. There is also an even cheaper Neo2-Twin cart, but I'm not sure if that works with it or not. I only have the Neo2-SD and Neo2-Pro for testing. I CAN say that the Neo3-SD/TF will NOT work since it doesn't have any psram in the GBA flash cart, or game flash for that matter. The Neo3-SD will only work on Myths with PSRAM inside the Myth itself, like the MD Myth or the SNES Myth. Quote Is there a package deal available? $99 for the MK III and another $89 for the Neo2 plus whatever shipping comes to is a little steep. There's no bundle deal, but like I mentioned above, there is a cheaper alternative to the Neo2-Pro, which is a bit expensive if you only plan on having the MKIII Myth. It's $20 less. http://www.ic2005.com/shop/product.php?productid=41&cat=0&featured=Y

Frank_fjs Joined: 19 Aug 2011 Posts: 115 Location: Australia	Posted: Sat Oct 22, 2011 2:23 am
	Thanks for the info Chilly Willy. :) Wish they all just used a standard SD interface, built into the flash cart itself. A lot cheaper and more convenient this way, and a lot less confusing! I'm still not sure which way to go, between the Myth or the Everdrive. I only want to play games and don't require any homebrew/software development tools. The FM chip of the Myth is super cool but already owning a Japanese MS not that important to me. I guess the one with the easiest transferring and loading of roms would suit me better, and the Everdrive looks to be the way to go and is a little bit cheaper.

Chilly Willy Joined: 23 Jan 2011 Posts: 65 Location: The Land of Enchantment	Posted: Sat Oct 22, 2011 6:47 am
	Frank_fjs wrote Thanks for the info Chilly Willy. :) Wish they all just used a standard SD interface, built into the flash cart itself. A lot cheaper and more convenient this way, and a lot less confusing! I'm still not sure which way to go, between the Myth or the Everdrive. I only want to play games and don't require any homebrew/software development tools. The FM chip of the Myth is super cool but already owning a Japanese MS not that important to me. I guess the one with the easiest transferring and loading of roms would suit me better, and the Everdrive looks to be the way to go and is a little bit cheaper. Yeah, if you don't need the extras, the Everdrive family is usually the best buy for the money. The Myth line is more expensive, but some people want/need to extras that come with them. The Myth stuff can be a little confusing as well, but it has a pretty good forum that's usually helpful in getting the info you need. One thing I'm looking forward to is the Everdrive for the PCE coming next year. The current flash cards for the PCE (including the NeoFlash one) aren't all that good.

Lan Di Joined: 26 Jun 2011 Posts: 18 Location: Southern California	Posted: Sun Oct 23, 2011 10:45 pm
	Frank_fjs wrote Silly question, will it work in a Japanese Master System, with the use of an adapter? Not that there's much point, just wondering is all. I don't know about the myth flash cart, but the Everdrive works with a Japanese Master System with a Tototek converter with full FM support. Check out my post....http://www.smspower.org/forums/viewtopic.php?t=12915

Frank_fjs Joined: 19 Aug 2011 Posts: 115 Location: Australia	Posted: Mon Oct 24, 2011 4:15 am
	Great info, thanks for sharing Lan Di. :) I do have the Tototek converter and a Japanese MS so I'm set. One thing that I just thought of re the Myth cart, I hook my console up via RGB SCART and it seems the Myth cart limits you to composite video only. I'd probably live with that if I didn't have a Japanese MD and wanted to experience some FM goodness, but then again for the cost of the Myth cart I'd rather just get the real thing, i.e. a Japanese MS.

Chilly Willy Joined: 23 Jan 2011 Posts: 65 Location: The Land of Enchantment	Posted: Mon Oct 24, 2011 6:00 am
	Frank_fjs wrote Great info, thanks for sharing Lan Di. :) I do have the Tototek converter and a Japanese MS so I'm set. One thing that I just thought of re the Myth cart, I hook my console up via RGB SCART and it seems the Myth cart limits you to composite video only. I'd probably live with that if I didn't have a Japanese MD and wanted to experience some FM goodness, but then again for the cost of the Myth cart I'd rather just get the real thing, i.e. a Japanese MS. Actually, you only need to pass the audio through the Myth. The video is only there to make cable hookup easier - one AV cable to the Myth, and one rca stereo cable from the Myth to the TV. The video is neither needed by the Myth, nor altered, merely passed through.

Bock Site Admin Joined: 08 Jul 2001 Posts: 8661 Location: Paris, France	Posted: Mon Oct 24, 2011 8:45 am
	Chilly Willy wrote Actually, you only need to pass the audio through the Myth. The video is only there to make cable hookup easier - one AV cable to the Myth, and one rca stereo cable from the Myth to the TV. The video is neither needed by the Myth, nor altered, merely passed through. This is good to know and be clarified. I was always put off by the idea of having to connect a SMS with RCA cables.

Frank_fjs Joined: 19 Aug 2011 Posts: 115 Location: Australia	Posted: Mon Oct 24, 2011 9:43 am
	Bock wrote Chilly Willy wrote Actually, you only need to pass the audio through the Myth. The video is only there to make cable hookup easier - one AV cable to the Myth, and one rca stereo cable from the Myth to the TV. The video is neither needed by the Myth, nor altered, merely passed through. This is good to know and be clarified. I was always put off by the idea of having to connect a SMS with RCA cables. +1, this should be mentioned in the product details as well I think.

MaRkiSH Joined: 13 Jul 2001 Posts: 184	Posted: Mon Oct 24, 2011 5:55 pm
MaRkiSH Joined: 13 Jul 2001 Posts: 184	I ordered a Master Everdrive a couple of weeks ago, but I've got one of viletim's FM boards installed on my Master System so I don't feel like I'd be missing out on much stuff I'm interested in. Plus I'd rather use SD than a GBA flashcart. Which is very creative.

Chilly Willy Joined: 23 Jan 2011 Posts: 65 Location: The Land of Enchantment	Posted: Wed Oct 26, 2011 5:04 am
	Frank_fjs wrote Bock wrote Chilly Willy wrote Actually, you only need to pass the audio through the Myth. The video is only there to make cable hookup easier - one AV cable to the Myth, and one rca stereo cable from the Myth to the TV. The video is neither needed by the Myth, nor altered, merely passed through. This is good to know and be clarified. I was always put off by the idea of having to connect a SMS with RCA cables. +1, this should be mentioned in the product details as well I think. We occasionally make suggestions about the product details on the forum. I've already had Dr.neo change the MD Myth combo product details. :)

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