CPU variants

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Beyond the well-studied 2A03G, we know of the following CPU revisions, both made by Ricoh and other manufacturers:

RP2A03 M2 duty cycle is 17/24 instead of 15/24 [1]. Lacks tonal noise mode. APU Frame Counter not restarted on reset. Has broken and disabled programmable interval timer on-die. Pin 30 connects to nothing. Other differences?
RP2A03E Pin 30 may connect to 6502 /RDY input.

CPU=RP2A03E 5K5 26.jpg

RP2A03G Reference model. Pin 30 enables a CPU test mode. Later runs may have introduced a DMC DMA bug [2].
RP2A03H No known differences from late RP2A03G.
RP2A04 Not actually a CPU at all, just a jumper in a 40-pin PDIP
RP2A07 input clock divider is 16. M2 duty cycle is 19/32 [3]. Changes to noise, DPCM, frame timer tables. Fixed DPCM RDY address bus glitches. Pin 30 connects to 6502 /RDY input.
RP2A07A no known differences relative to 2A07letterless

CPU=RP2A07A 2JM 3L.jpg

MG-P-501 Micro Genius-made clone. Die has the same (UMC) © Ⓜ B6167F marking as a UA6527P.
UA6527 UMC-made clone of 2A03G. Has swapped pulse channel duty cycles.

CPU=UA6527-8909-BS.jpg CPU=UA6527-9310-CG-C12520.jpg

UA6527P UMC-made clone of 2A03G for compatibility with NTSC software in PAL countries. input clock divider is 15. Otherwise believed same as 6527.

Two revisions exist: before mid-1990 (which has UMC logo on left) and after-mid-1990 (which has UMC logo on top). It is said that old UMC CPU has broken DMC reader function [4]. Addidionally it has input clock divider equals to 16 in contrary to the 15 present in newer one, that would explain why some games work differently (for example: CodeMasters' titles)

One revision has (UMC) © Ⓜ B6167F 1989 09 on the die.

Ua6527p old.png Ua6527p new.png

UA6540 UMC-made clone of 2A07 [5]. Has swapped pulse duty cycles.

CPU=UA6540-8834S.jpg

UM6557 Believed to be a 100% duplicate of UA6527, for use in SECAM regions.
UM6561xx-1 NES-on-a-chip for NTSC. Revisions "xx" AF, BF, CF, F known. Earlier revisions (which?) CPU half believed identical to UA6527; later revisions correct pulse channel duties.
UM6561xx-2 NES-on-a-chip for PAL-B. Revisions "xx" AF, BF, CF, F known. Earlier revisions (which?) CPU half believed identical to UA6527P; later revisions correct pulse channel duties.

"AF" revision pulse wave duties observed to be same as 2A03.

T1818 ??-made NES-on-a-chip, NTSC timing. Believed to exist, but evidence currently scant.
T1818P ??-made NES-on-a-chip[[6]. Requires external 2 KiB RAMs for CPU and PPU. Swapped pulse duty cycles.
TA-03N ??-made clone of 2A03G. Pin 30 selects input clock divider?

CPU=TA-03N 6527 9250.jpg

TA-03NP ??-made clone of 2A03G for NTSC compatibility in PAL countries. Input clock divider is 15.
TA-03NP1 ??-made clone of 2A03G for NTSC compatibility in PAL countries. Input clock divider is 15. Fixed DPCM problems?
PM03 Gradiente-made clone of 2A03G. [7]
GS870007 (Goldstar??)-made clone of 2A03 - has functioning decimal mode? [8]
KC-6005 Found in MT777-DX famiclone, behaves exactly like UA6527P

CPU=KC-6005.jpg

6005B CPU=6005B.jpg
2011 CPU=2011.jpg
“2A03E” Assumed from USC foundry, because found with a USC 2A02E

CPU=2A03E 9122A 422951.jpg

If you know of other differences or other revisions, please add them!

See also