Atari development news, April / May roundup

Bus error Apollo V4 Stand alone debut

As I recently started tinkering with V4SA and it looks like nice Atari TOS clone I’ve opened page on Bus Error Atari development wiki to gather all latest info about it’s Atari side. Here’s direct link.

    Uiptool V4SA ethernet driver

    To make development little easier on V4SA (reduce manual shuffling of micro sd carts) I’ve started working on Uiptool V4SA driver. I’ve managed to make it work partially – DHCP is properly configured, but TCP packets have 100% timeout. Basically any request from web browser fails right away and there’s no communication between browser and UIPTool. Development slowed down, because of lack of documentation of ethernet port in v4sa, so everything looks like running around with screw driver and poking hardware from different angles.

      UIPTool on V4SA under EMUTOS talks to DHCP server and retrieves assigned ip.

      OPL3 Atari ST cartridge development progress

      I’ve made some tests on first prototype board (the ugly one), wrote driver (,which is much smaller than for any other OPL3 device I’ve tested) and I’ve checked it’s operation with logic analyzer. This indicated that ST interface signal wise works as it should.

      STe talks with PCB via cartridge port, WR in low state and all control lines set to LOW(0) state. This at least in theory should trigger write to OPL3 data bus.OPL3 clock, generated on board is on top (orange).

      Unfortunately OPL / DAC doesn’t respond properly, some weird signals are outputted via YAC-512-M channels output.

      Good thing is that I’ve verified that MMU burning doesn’t occur and ST can boot to TOS and actually could write preliminary drivers and debug them. So it’s another achievement unlocked :).

      Simultanously I’ve sent to production another board version with fixed issues mentioned in previous post, I’ve recieved it, assembled and tested it. Here it is:

      OPL3 Dev Cartridge prototype 2
      This time pcb has proper 30 degree chisel, on left pcb of NetUSBee by Lotharek (certainly Atari ST cartridge port killer), left OPL3 ST cart prototype 2
      New PCB at least fits short ST cartridge port
      ST OPL3 cart dev board prototype 2 (top)
      ST OPL3 cart dev board prototype 2 (bottom)

      I hoped that it will work better and fix issues with DAC output or maybe it will show that chips I’ve soldered, but it didn’t. Footprints were ok, board fits into ST, but DAC output is quite different from what I’ve expected. Made comparision with OPL3LPT output and my conclusion is that’s something wrong here on signal level or DAC/OPL chips that I have might be fake or broken. Because all of them are SMT it’s hard to replace them to check other ones. I don’t have hot air station yet to have a possibility to remove them easily. I still have to nail down the issue and why it happens.

      Healthy OPL3 channel output on one of the YAC-512-M channels on OPL3LPT
      Output from DAC / YAC-512-M on OPL3 ST cart
      Same output on OPL3 ST cart, but magnified, yes, looks like saw, it doesn’t change, so obviously something wrong is going there.

      Atari ST OPL2 cartridge

      I’ve prepared ST OPL2 cartridge version (schematics and pcb), it’s partially based on OPL2 Arduino sound board, still I have to make some minor fixes to footprints / pcb before I send this to manufacturer and order parts. It will be using nearly the same drivers as OPL3 cart.

      So this more or less, what was going on lately. See you next time…

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