I've continued looing at the C65 roms. Technically only the latest rom is C65, the earlier ones are C64DX. The earliest ROM (v0.9.910111) is hardcoded to set the CIA TOD for 60hz. It could still be used on a PAL VIC3, it's just the TOD clock would be wrong. Like all good commodore products this may have been what happened (the commodore lcd prototype has some shameful bugs). But whatever system this came from would be a candidate for NTSC hardware. F08D: A9 08 lda #$08 F08F: 8D 0E DC sta $dc0e F092: 8D 0E DD sta $dd0e The others detect PAL/NTSC like the C64 does and uses that to set the CIA TOD correctly. So you can't tell from the ROM version, you could probably use PRINT PEEK(DEC("DC0E")) AND 128 F0C6: A2 FF ldx #$ff F0C8: AD 11 D0 lda $d011 F0CB: 10 FB bpl $f0c8 F0CD: A9 08 lda #$08 F0CF: CD 12 D0 cmp $d012 F0D2: 90 06 bcc $f0da F0D4: AD 11 D0 lda $d011 F0D7: 30 F4 bmi $f0cd F0D9: E8 inx F0DA: 8E 03 11 stx $1103 F0DD: 8A txa F0DE: 29 80 and #$80 F0E0: 09 08 ora #$08 F0E2: 8D 0E DC sta $dc0e F0E5: 8D 0E DD sta $dd0e ($80 is 50hz/60hz bit) These are the rom versions I looked at. c64dx v0.9.910111 ntsc only v0.9b.910429 pal/ntsc v0.9b.910523 pal/ntsc v0.9b.910626 pal/ntsc v0.9b.910828 pal/ntsc c65 v0.9b.911001 pal/ntsc On 04/11/2017 09:13, smf wrote: > This suggests all the hardware was PAL > > http://www.floodgap.com/retrobits/ckb/secret/65.html > > But there is an NTSC rom, which looks like it changes the refresh rate > but not the video standard. > Message was sent through the cbm-hackers mailing listReceived on 2017-11-05 14:00:02
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