Registers

Old3DS	Name	Address	Width
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_PDATA - DSP Transfer Data Read FIFO (R)

0-15  Data (one stage of the 16-stage Read FIFO)

DSP_PDATA - DSP Transfer Data Write FIFO (W)

0-15  Data (one stage of the 16-stage Write FIFO)

DSP_PADR - DSP Transfer Address (W)

0-15  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)

 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_PSTS - DSP Status (R) (16bit)

 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_PSEM - ARM11-to-DSP Semaphore (16bit)

 0-15  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_PMASK - DSP-to-ARM11 Semaphore Mask (16bit)

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

DSP_PCLEAR - DSP-to-ARM11 Semaphore Clear (W) (16bit)

 0-15  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_SEM - DSP-to-ARM11 Semaphore Data (R) (16bit)

 0-15  DSP-to-ARM11 Semaphore 0..15 Flags (0=Off, 1=On)

Reportedly these flags are received in DSP-to-ARM11 direction.

DSP_CMDX - DSP Command Reg. X (R/W) (ARM11 to DSP) (16bit)

 0-15  Command/Data to DSP

DSP_REPX - DSP Reply Register X (R) (DSP to ARM11) (16bit)

 0-15  Reply/Data from DSP

DSP Registers

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