User contributions for Quietust

16 May 2011

• 02:2202:22, 16 May 2011 diff hist −274‎ File:2a03 map.jpg ‎ created a chip images index page on my site

14 May 2011

• 17:1617:16, 14 May 2011 diff hist +398‎ Talk:APU Sweep ‎ food for thought and/or research
• 16:5616:56, 14 May 2011 diff hist +14‎ APU Sweep ‎ clarify
• 16:4616:46, 14 May 2011 diff hist +104‎ APU Sweep ‎ the problem isn't in pulse 2, but in pulse 1 - pulse 2 adds the two's complement during subtraction (as it should), but pulse 1 adds the ONE'S complement due to its carry input being hardwired
• 16:3716:37, 14 May 2011 diff hist +131‎ APU Pulse ‎ The duty cycle counter actually counts downward (since it's triggered by frequency counter underflow), but it's initialized to 000 rather than 111, which explains the waveform sequences

11 May 2011

• 03:1803:18, 11 May 2011 diff hist −10‎ File:Apu address.jpg ‎ it also overrides the noise channel's LFSR output and appears to also stop the triangle channel from being clocked; I don't know what it does to DPCM, but it's probably something similar current
• 03:0303:03, 11 May 2011 diff hist +12‎ File:Apu address.jpg ‎ setting $401A.7 prevents the square channels from outputting 0000, whether from the duty cycle generator, the sweep unit, or the length counter; the effect on triangle/noise/PCM is still unclear

10 May 2011

• 15:4615:46, 10 May 2011 diff hist +700‎ Talk:APU Frame Counter ‎No edit summary
• 00:4500:45, 10 May 2011 diff hist +462‎ N Talk:APU Sweep ‎ an amusing thing I noticed a while ago - the actual reason why the sweep units in the 2 square channels behave slightly differently

9 May 2011

• 15:3415:34, 9 May 2011 diff hist +9‎ CPU pinout ‎ STR/E44/E45 are better known as OUT0/OUT1/OUT2; also, strobe is OUT, not D0
• 15:2115:21, 9 May 2011 diff hist +720‎ Talk:CPU pinout ‎ located the main side effect of pulling pin 30 high - all readable registers in $4000-$401F go internal, so the joypads stop working

7 May 2011

• 20:3320:33, 7 May 2011 diff hist −123‎ m Talk:CPU pinout ‎ traced enough of it to determine this - if both /RESET and pin 30 are low, then the output drivers for M2 will be disabled and the pin will float
• 19:4519:45, 7 May 2011 diff hist +634‎ m Talk:CPU pinout ‎ figured out the part that goes to M2 - it's merged with /RESET

2 May 2011

• 15:4015:40, 2 May 2011 diff hist +69‎ m User:Quietust ‎ not yet tested, though
• 15:3815:38, 2 May 2011 diff hist −65‎ m Nintendulator ‎ does not use inline assembly anymore
• 15:3815:38, 2 May 2011 diff hist +372‎ User:Quietust ‎ put RP2A03G die analysis findings somewhere convenient

29 April 2011

• 16:4916:49, 29 April 2011 diff hist +37‎ Talk:CPU pinout ‎No edit summary
• 16:3216:32, 29 April 2011 diff hist +463‎ File:2a03 map.jpg ‎ fully traced every single layer of the RP2A03G - these have also been submitted to visual6502.org for potential simulation

17 April 2011

• 17:2617:26, 17 April 2011 diff hist +781‎ N Talk:Sunsoft FME-7 ‎ ...

2 April 2011

• 01:5001:50, 2 April 2011 diff hist +119‎ m File:2a03 map.jpg ‎No edit summary
• 01:4801:48, 2 April 2011 diff hist +245‎ N File:2a03 map.jpg ‎ A rough diagram of where everything is physically located on the RP2A03G. The clock divider, not highlighted, is at the far right. The purpose of the large section at the upper right is not known - none of it has any connection to anything else.

30 March 2011

• 15:5215:52, 30 March 2011 diff hist 0‎ m Talk:CPU pinout ‎No edit summary
• 15:5115:51, 30 March 2011 diff hist +82‎ m Talk:CPU pinout ‎ my mistake - they're all enhancement mode (VCC->gate = source and drain connected), but ones with "thick" gates are effectively resistors when off (where "thicker" == lower resistance)

20 March 2011

• 00:1900:19, 20 March 2011 diff hist +42‎ Talk:CPU pinout ‎ getting better at reading these images, but not quite good enough...

1 March 2011

• 19:4719:47, 1 March 2011 diff hist +262‎ m Talk:CPU pinout ‎No edit summary

28 February 2011

• 03:0503:05, 28 February 2011 diff hist +148‎ m Talk:INES Mapper 068 ‎ found it

27 February 2011

• 21:5921:59, 27 February 2011 diff hist +452‎ N Talk:INES Mapper 068 ‎ ...what about 1-screen mirroring?
• 16:5316:53, 27 February 2011 diff hist +58‎ INES Mapper 068 ‎ clarify nametable registers - $C000 overrides the lower nametable and $D000 overrides the upper nametable, then mirroring gets done accordingly
• 04:1504:15, 27 February 2011 diff hist +180‎ N Talk:CPU pinout ‎ I think I've figured it out...
• 04:0204:02, 27 February 2011 diff hist +48‎ File:Apu address.jpg ‎ traced out all of the registers, and I've located what W$401A is connected to - triangle wave position (D0-D4) and something I don't recognize (D7)

12 February 2011

• 03:3703:37, 12 February 2011 diff hist 0‎ m Cartridge connector ‎ *ahem*

4 February 2011

• 14:0414:04, 4 February 2011 diff hist +15‎ m Programming with unofficial opcodes ‎ →‎Combined operations: s/N/Z/
• 13:5613:56, 4 February 2011 diff hist −67‎ Programming with unofficial opcodes ‎ it most definitely does set N - blargg's instr_test-v3 fails if it doesn't

2 February 2011

• 16:1116:11, 2 February 2011 diff hist +194‎ Myths ‎ →‎Old tutorials: people need to know WHY the gbaguy tutorial is wrong - explicitly point out some of its mistakes
• 16:0616:06, 2 February 2011 diff hist +52‎ Myths ‎ →‎Mappers: the VRC6 uses 16K/8K/8K banking, and the MMC5 happens to support this mode

31 January 2011

• 17:4417:44, 31 January 2011 diff hist +133‎ m INES Mapper 119 ‎ →‎Variants
• 17:4217:42, 31 January 2011 diff hist +84‎ m INES Mapper 192 ‎ better comparison

24 January 2011

• 15:3115:31, 24 January 2011 diff hist +122‎ m File:Apu address.jpg ‎ anybody capable of interpreting these images is welcome to figure out how to enable these extra registers...
• 15:2615:26, 24 January 2011 diff hist +509‎ N File:Apu address.jpg ‎ The NES APU's address decoder, generating enables for all reads/writes within $4000-$401F. Of very special note are the 4 signals at the very top for readable registers at $4018 (pulse 0 output on D0-D3 and pulse 1 output on D4-D7), $4019 (triangle outpu
• 00:2900:29, 24 January 2011 diff hist +13‎ m Talk:APU DMC ‎ this too
• 00:1600:16, 24 January 2011 diff hist +88‎ m Talk:APU Noise ‎No edit summary

23 January 2011

• 17:1017:10, 23 January 2011 diff hist +48‎ m Talk:APU Frame Counter ‎No edit summary
• 17:0917:09, 23 January 2011 diff hist +512‎ N Talk:APU Frame Counter ‎ Created page with 'The frame counter [http://uxul.org/~noname/chips/cpu-2/no-metal/stitched/final/ on the die] seems to be a 15-bit linear feedback shift register (with taps at the 14th and 15th bi…'
• 05:0005:00, 23 January 2011 diff hist +443‎ N Talk:APU DMC ‎ Created page with 'Similarly to the noise channel, the DPCM channel's frequency counter [http://uxul.org/~noname/chips/cpu-2/no-metal/stitched/final/ on the die] is a '''9-bit linear …'
• 05:0005:00, 23 January 2011 diff hist +5‎ m Talk:APU Noise ‎No edit summary
• 04:5804:58, 23 January 2011 diff hist +439‎ N Talk:APU Noise ‎ more food for thought
• 03:3003:30, 23 January 2011 diff hist +289‎ N Talk:APU Length Counter ‎ Created page with 'Food for thought: the values in the length counter table [http://uxul.org/~noname/chips/cpu-2/no-metal/stitched/final/ on the die] (bottom of the chip, just left of center), '''o…'

18 January 2011

• 15:4715:47, 18 January 2011 diff hist +330‎ N File:Palette.jpg ‎ Palette RAM as physically implemented within the PPU. Note the incomplete address decoding which results in $10/$14/$18/$1C being mirrors of $00/$04/$08/$0C. Also of note, palette RAM bits are significantly larger than those of OAM (which are believed to

14 January 2011

• 20:4020:40, 14 January 2011 diff hist −52‎ m NES 2.0 ‎No edit summary
• 04:5204:52, 14 January 2011 diff hist +283‎ m Talk:NES 2.0 ‎ Another random observation, probably too late to be useful