RegistersEdit

Old3DS Name Physical Address Width Used by
Yes DSP_PDATA 0x10203000 2
Yes DSP_PADR 0x10203004 2
Yes DSP_PCFG 0x10203008 2
Yes DSP_PSTS 0x1020300C 2
Yes DSP_PSEM 0x10203010 2
Yes DSP_PMASK 0x10203014 2
Yes DSP_PCLEAR 0x10203018 2
Yes DSP_SEM 0x1020301C 2
Yes DSP_CMD0 0x10203020 2
Yes DSP_REP0 0x10203024 2
Yes DSP_CMD1 0x10203028 2
Yes DSP_REP1 0x1020302C 2
Yes DSP_CMD2 0x10203030 2
Yes DSP_REP2 0x10203034 2

DSP_PDATAEdit

Data (one stage of the 16-stage Read FIFO).

DSP_PADREdit

Lower 16bit of Address in DSP Memory. Note: The upper 16bit of Address must be configued in the DMA register (inside of the DSP).

DSP_PCFG - DSP Configuration (R/W) (16bit)Edit

Bits Description
0 DSP Reset (0=Release, 1=Reset) ;should be held "1" for 8 DSP clks
1 Address Auto-Increment (0=Off, 1=On)
2-3 DSP Read Data Length (0=1 word, 1=8 words, 2=16 words, 3=Free-Run)
4 DSP Read Start Flag (mem transfer via Read FIFO) (1=Start)
5 Interrupt Enable Read FIFO Full (0=Off, 1=On)
6 Interrupt Enable Read FIFO Not-Empty (0=Off, 1=On)
7 Interrupt Enable Write FIFO Full (0=Off, 1=On)
8 Interrupt Enable Write FIFO Empty (0=Off, 1=On)
9 Interrupt Enable Reply Register 0 (0=Off, 1=On)
10 Interrupt Enable Reply Register 1 (0=Off, 1=On)
11 Interrupt Enable Reply Register 2 (0=Off, 1=On)
12-15 DSP Memory Transfer (0=Data Memory, 1=MMIO Register, 5=Program Memory)

DSP_PSTSEdit

Bits Description
0 Read Transfer Underway Flag (0=No, 1=Yes/From DSP Memory)
1 Write Transfer Underway Flag (0=No, 1=Yes/To DSP Memory)
2 Peripheral Reset Flag (0=No/Ready, 1=Reset/Busy)
3-4 Unused
5 Read FIFO Full Flag (0=No, 1=Yes)
6 Read FIFO Not-Empty Flag (0=No, 1=Yes) ;ARM11 may read DSP_PDATA
7 Write FIFO Full Flag (0=No, 1=Yes)
8 Write FIFO Empty Flag (0=No, 1=Yes)
9 Semaphore IRQ Flag (0=None, 1=IRQ)
10 Reply Register 0 Update Flag (0=Was Written by DSP, 1=No)
11 Reply Register 1 Update Flag (0=Was Written by DSP, 1=No)
12 Reply Register 2 Update Flag (0=Was Written by DSP, 1=No)
13 Command Register 0 Read Flag (0=Was Read by DSP, 1=No)
14 Command Register 1 Read Flag (0=Was Read by DSP, 1=No)
15 Command Register 2 Read Flag (0=Was Read by DSP, 1=No)

Unknown if/when bit10-15 get reset... maybe after reading the status?

DSP_PSEMEdit

DSP-to-ARM11 Semaphore 0..15 Flags (0=Off, 1=On). Reportedly these flags are sent in ARM11-to-DSP direction. Confusingly, the other DSP_Pxxx registers are for opposite direction?

DSP_PMASKEdit

DSP-to-ARM11 Semaphore 0..15 Interrupt Disable (0=Enable, 1=Disable)

DSP_PCLEAREdit

DSP-to-ARM11 Semaphore 0..15 Clear (0=No Change, 1=Clear). Reportedly clears bits in DSP_PSEM. [that's probably nonsense, clearing bits in DSP_SEM would make more sense]

DSP_SEMEdit

DSP-to-ARM11 Semaphore 0..15 Flags (0=Off, 1=On). Reportedly these flags are received in DSP-to-ARM11 direction.

DSP_CMDXEdit

Command/Data to DSP.

DSP_REPXEdit

Reply/Data from DSP.