Dropcheck

On the PAL/GAL conversions, I have not had a chance to test reifsnyderb's files yet. And I haven't been able to fully test tf_hh's yet. So that is also still up in the air. Added to the test list. I'd have to say probably tf_hh's PALtoGAL for PAL A is good. As I get to the speech and modem tests, I'll know more.

Well the board isn't quite ready for prime time yet. I have done a few more tests today. I wanted to start with the basics first. Once I have those nailed down, then I'll start with the speech chip and modem. It's turning out to be a little more delicate than I had anticipated. Since there is no case, I'm having to balance the loose 1200XL keyboard and top cover over the bare board and try like hell not to knock it off it's paper box spacers and down on the live board. That wouldn't be very much fun. 🙃 So far: SIO appears to work. Using an XF551, I was able to boot and load into memory DOS 2.5 and then bring up the DOS menu. Still to test is whether I can manipulate disks and use other devices on the SIO port. Cartridge port appears to work. I was able to load MULE from a cartridge. I'll try other cartridges over the next couple of days. But either I have wonky 1200XL keyboard or there is an issue with the 1450XL circuitry for the keyboard. I was not able to consistently get keys pressed to echo to the screen. The OPTION button worked once. The other buttons START and SELECT aren't at all. I am getting a power light on the current 1200XL keyboard. I'll have to partially disassemble my other 1200XL to try it's keyboard next. Sound is working. No apparent problem there. Video needs to be clean up a bit, but no artifacts or dropping out of sections of screen, so ram appears to be okay. Have verified the 1450XL will boot with either the normal Freddie or Lotherak's Freddie CPLD by Candle. Joysticks are still a bit unknown yet. I don't have another game cart to try right now that only uses joysticks and not the OPTION/SELECT buttons too. I thought about trying a disk-based game and I'll see if I've got something in my archives. RF out is not tested yet. I'm having problems finding my RF cable. PBI is not tested yet for much the same reason. I can't seem to find the one or two PBI devices I have. I put them away somewhere and I've forgotten where I put them. 😔 I'll update as I resolve missing equipment and the keyboard issue. But it is looking good. Eventually I plan a video to show proof of function. It's just going to take a few days yet.

I fell out of my chair! It booted! Crappy picture. I can fix that. No knowing what else is or isn't working, but it is booting into BASIC. I don't want to breath too hard, I might jinx it. I fixed the RP1pin4 pullup signal on ~IRQ1 and C66. I decided to try tf_hh's files first, burned them into the GAL16V8 dip chips I had and inserted them into the board. And crossed my fingers. Then flipped the power button. IT BOOTED! I think kheller2's board scared it into working. I'm taking the rest of the night off. I think I've earned it. 😃

hkeller2's board came in today, as well as the Mouser order. I found another two minor errors that I can fix easily. RP1pin4 should be connected to ~IRQ1 signal and C66 is not connected at all. Should be +5V on one end and GND on the other. I have received new PAL2GAL files from tf_hh that I'll burn and try out on my board then. As well as reifsnyderb's. Between the two we should have a valid set. If that does not bring up my board, then I'll dig into comparing hkeller2's board powered signals with my board.

At this point not much is going to happen until I get kheller2's working board in Wednesday. After that I may need to verify with you on some things if I can. 😀

Yes.

Have just verified on the board that U8pin8 and U12pin14 are tied together. Could it be different events triggering a different signal?

Sorry was editing my previous statement after a few seconds of thought.

By the board truth U11 pin 18 is not generating the MPE signal. We know that since there is no trace from pin 18. So in this case the schematics are wrong. MPE is actually coming in on the PBI bus pin J3pin 43. But then again it sure seems like NOT INTMPE is being created twice. Might the schematic be wrong again?

Should have the chips in by Tuesday/Wednesday late. Will report back. Thanks! 🙂

I've tried paltogal.exe and a couple other dos based programs. Not sure enough of the output, especially on the registered pal to go with it. Since we have the PAL C equations already, that would probably be the best place to start converting from PAL to "GAL". If we have to, we can go back to the binary conversion process. So using the pinouts in the Atari PAL equation sheet for PAL C, do you think it would be difficult to translate the PAL syntax to Atmel ATF16V8B? Pin 18 doesn't even come into play, since no trace to any other part on the board exists. Other circuitry appears to handle that signal. ATF16V8B chips ordered.

So far I am seeing it on R120pin1, PBI J3pin43 and the Parallel Drive Connector J12pin25. Which makes sense since that is a signal unique to an external connection on the PBI. Unfortunately that .jed is the PAL binary. Which is fine if you have a way to buy and burn PAL chips. Most people including me don't have the programmer necessary. We do have the newer variety that can do GALs. Hopefully now reifsnyderb will be able to re-create the PAL C for the Atmel ATF16V8B chip.

Thanks! We'll have to wait for AtariGeezer to report back on PAL C. If you are sure you can do all three with the ATF 16V8B chips, I'll make a quick mini-order to Mouser. I don't currently have a supply. Are they re-programmable like normal GALs?

The schematics in this case appear to be wrong. Or an engineering change was made after the schematics were drawn. I think you'll find the MPE signal goes to U8 pin 9.

A question......? This MMU is used in the 1450XL? What is the chip designation?