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Category: AVR

Avr

First Quickdev16 PCB is working

Not “out of the box” but with only slightly changes on the software part, the new quickdev16 PCBs are working. Their shape fit the SNES cartslot, the changes in hardware design and parts worked out great and we have a kind of stable firmware and upload tool.

When you turn on the SNES, the microcontroller extracts a small loader-rom into the cartridge RAM that is mapped into the SNES addressspace. This one copies itself to SNES’s WRAM and jumps into it. So the cartridge RAM is unaccessed and we can safely switch back to the AVR mode to push a real payload rom onto the cartridge. We are also working on a shared memory function so that we can use the cartridge RAM
to exchange infomation between the AVR and the SNES. This will be used to display a proper Progressbar
while uploading a rom.

As usal you can use our patched version of ucon64 – even under windows – to upload a game to the quickdev16. When the upload is done, the SNES reset line is pulled by quickdev16 and the game starts. When you press the reset button, you only reset the game, not the quickdev16 – it acts like a normal cart. When you press the reset button during the upload process or while watching the loaderscreen, you reset the quickdev and can abort uploads or just restart the quickdev16 – thats a really usefull feature. To initiate the upload of a new game, just start the upload process with ucon, the quickdev switches to the loader mode by itself and receives the new ROM.

So the steps are now to improve the loader code, finish the progress bar stuff, figure out how to solder the PCBs faster than now and add some minor features. Stay tuned for updates, it’s not too long to the release.

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We call it ‘QuickDev16 USB’

Finally we found a better name for the snesram and renamed it to ‘QuickDev16 USB’. Final PCB layouts are ready and will be send to china soon. So in about 2 weeks we will have our first PCBs.

Confirmed Features:

  • 16 MBit Sram for Rom storage
  • ATmega644 MCU for housekeeping
  • USB connection for ROM upload
  • ucon64 software compatibel
  • PAL/NTSC CICs are supported
  • Lo/Hirom support
  • Reset trigger from cartridge possible
  • AVR USB Bootloader for quick firmware uploads
  • Snes bootloader intro
  • Snes powered, no power source needed

Stay tuned for more features, especially debugging helpers

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Features Features Features…

Things are going well. Have added some features to the software side and also got some stuff working hardware wise.

Can confirm that US/JAP roms are working.Only tested EU roms before. Used my japanese Nintendo junior and a japanese CIC to confirm that the snesram is working with that setup too.

Max and i added an bootloader to the AVR software toolchain. Now its possible to flash the AVR firmware via the same USB cable as for the normal bulk transfer. So no extra ISP programmer is needed to change the AVR firmware. This is super fast, can flash the 16kb client side firmware in like 3 secs.

Added a reset line trigger to the snes bus. Now the client software can reset the snes after uploading the software. So its possbile to push a rom via ucon64 from the pc and then reset is done by ucon64 and the firmware. No interaction needed from there.

Max is refactoring the schematics so that we can send them over to the pcb fab soon. Stay tuned.

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New Hardware Revision

Max took a quick break from his vacations and was able to work on the new hardware revision of the snesram. Its mainly a bugfix to version 0.1 . We also did some cost reductions. Most obvious is to go for 2 Mbyte of sram instead of 4Mbyte. It just make the PCB smaller and less complex. I guess this should be alright with most peoples needs.
We gonna print a small amount of PCB and will take pre-orders as soon as we know they will arrive. Not sure about the final price, depends on the PCB costs and if we get
better prices for the sram. Stay tuned.

Changes in Detail:

* Add AVR reset button
* Fix CS bug and add additional gate
* Reduce to 2 Mbytes for 16 Mbits games
* Snes reset line trigger
* No FTDI for the serial line
* Add RX/TX to pin header
* Model Snes connector header
* 1,2 mm PCB for direct plug
* Blacksolder Mask
* White silk screen

Preview:

Front
Front
Back
Back
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