Talk:Non-power-of-two ROM size: Difference between revisions

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'' The most notable exception on NES is Action 52, which has four footprints for 512Kx8 (4 Mbit) PRG ROMs, of which three are populated totaling 12 Mbit (1.5 MiB). ''' Which PCB has footprint for 4 PRG ROMs? [[User:Krzysiobal|Krzysiobal]] ([[User talk:Krzysiobal|talk]]) 09:45, 24 June 2021 (MDT)
'' The most notable exception on NES is Action 52, which has four footprints for 512Kx8 (4 Mbit) PRG ROMs, of which three are populated totaling 12 Mbit (1.5 MiB). ''' Which PCB has footprint for 4 PRG ROMs? [[User:Krzysiobal|Krzysiobal]] ([[User talk:Krzysiobal|talk]]) 09:45, 24 June 2021 (MDT)
:I'll have to review my sources and edit if my recollection was wrong. If the production PCB has three footprints, is there a decoder output line that goes NC? --[[User:Tepples|Tepples]] ([[User talk:Tepples|talk]]) 09:03, 27 June 2021 (MDT)
:I'll have to review my sources and edit if my recollection was wrong. If the production PCB has three footprints, is there a decoder output line that goes NC? --[[User:Tepples|Tepples]] ([[User talk:Tepples|talk]]) 09:03, 27 June 2021 (MDT)
::PAL16L8 is responsible for enabling ROMs in Action52. I don't have the PCB to confirm operation, but if wiki says there is `open bus` when bank 2 is selected, then it means the logic formula inside PAL does not enable any ROM when this bank is selected. [[User:Krzysiobal|Krzysiobal]] ([[User talk:Krzysiobal|talk]]) 10:43, 27 June 2021 (MDT)

Latest revision as of 16:43, 27 June 2021

Action 52 PCB

The most notable exception on NES is Action 52, which has four footprints for 512Kx8 (4 Mbit) PRG ROMs, of which three are populated totaling 12 Mbit (1.5 MiB). ' Which PCB has footprint for 4 PRG ROMs? Krzysiobal (talk) 09:45, 24 June 2021 (MDT)

I'll have to review my sources and edit if my recollection was wrong. If the production PCB has three footprints, is there a decoder output line that goes NC? --Tepples (talk) 09:03, 27 June 2021 (MDT)
PAL16L8 is responsible for enabling ROMs in Action52. I don't have the PCB to confirm operation, but if wiki says there is `open bus` when bank 2 is selected, then it means the logic formula inside PAL does not enable any ROM when this bank is selected. Krzysiobal (talk) 10:43, 27 June 2021 (MDT)