- Joined: 24 Sep 2013
- Posts: 141
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Serial bootloader for SMS
 Posted: Fri Dec 30, 2016 2:18 am
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Just completed a serial bootloader for the Master System in which you can upload and execute a ROM from your PC to the console using a serial port.
Attached ROMs and video showing the process.
I want to do automated testing on the SMS hardware itself so to streamline it I needed a way to push code directly from the PC into the console, reusing the UART implementation on the controller port an the XMODEM protocol I managed to have a way to upload and execute small relocatable ROMs on the Master System with minor intervention and no cartridge reflashing.
The bootloader has been added to my in-progress BIOS replacement ROM, which will, in a future, try to download a ROM on powerup so I can fully automate the console testing.
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- Joined: 25 Feb 2013
- Posts: 384
- Location: Osaka
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Posted: Sat Dec 31, 2016 3:38 am
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what speeds are you achieving? (bytes/s)
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- Site Admin
- Joined: 08 Jul 2001
- Posts: 8652
- Location: Paris, France
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Posted: Sat Dec 31, 2016 10:15 am
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It is great that it's using the serial port, but if a MOD is required (for the BIOS) why not go full way and use USB for possibly faster speed?
I could use a software similar to my "smsdump" tool, that copies itself to ram, allowing the card/card/source to be unplugged, then can dump carts and send them over xmodem on the serial port. :)
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- Joined: 24 Sep 2013
- Posts: 141
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Posted: Sun Jan 01, 2017 7:21 pm
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Quote if a MOD is required
It can run from any of the available ROM sources, be it BIOS, Cartridge, Card or Expansion port. The example shown has been done using the card slot and no BIOS modification, even though the original purpose was making a BIOS replacement I think it will stay as a toolkit ROM because I am too lazy to heavily mod my SMS :P
Quote ..."smsdump" tool, that copies itself to ram, allowing the card/card/source to be unplugged, then can dump carts and send them over xmodem on the serial port.
Tried that with a cartridge slot board, didn't have much success, stuff gets corrupted when plugging the card off. Not that I tried too hard anyway but I would suggest using the card slot to do any ROM tool loading before dumping since it is generally not used and is booted first on SMS. Otherwise, if you can fit the tool ROM in less than ~4K of ROM it could be loaded by this bootloader as-is.
Quote what speeds are you achieving? (bytes/s)
As of right now my UART code implements a 4800bps serial port. Further improvements can be done, especially on the SMS-to-PC link speed but have not bothered yet.
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