Dragon Ball 3 - Gokuu Den PCB TTL

[krzysiobal]

Oh, I realized that because all regs are under $8000, so no bus conflicts occur and PRG-ROM-/CE can be directly diven by CPU-/ROMSEL, freeing up 1/2 of 139 which can be used as PPU-A12 inverter, and so the 7474 can be used to acknowledge IRQ:

[zxbdragon]

After I get divorced, I'll scan your PCB

It's unfortunate to marry such a bitch

[Ben Boldt]

After I get divorced, I'll scan your PCB

It's unfortunate to marry such a bitch

HAHahahah

Careful she doesn't take half of the PCB.

[zxbdragon]

After I get divorced, I'll scan your PCB

It's unfortunate to marry such a bitch

HAHahahah

Careful she doesn't take half of the PCB.

I lost 2 million RMB.

She scorned the rubbish

[krzysiobal]

Thanks to zxbdragon photos I was able to rev-en this PCB. Surprisingly I was almost 100% accurate with my guesses, here are differences:
* CHR-ROM order is 100069C + 100068C, not vice versa
* MJ338986 is 74191 with CLK and /CNTEN pins swapped (pin4=CLK, pin14=/CNTEN)
* $600A.0 must be written with 0 to acknowledge IRQ
* counter's CLK = (not $600A.0 OR M2), /CNTEN = GND (but the behaviour is exactly the same, just the fourth OR gate is wasted that way)

[zxbdragon]

Thanks to zxbdragon photos I was able to rev-en this PCB. Surprisingly I was almost 100% accurate with my guesses, here are differences:
* CHR-ROM order is 100069C + 100068C, not vice versa
* MJ338986 is 74191 with CLK and /CNTEN pins swapped (pin4=CLK, pin14=/CNTEN)
* $600A.0 must be written with 0 to acknowledge IRQ
* counter's CLK = (not $600A.0 OR M2), /CNTEN = GND (but the behaviour is exactly the same, just the fourth OR gate is wasted that way)

Why does 8 bit size GG code not work?