Registers

Old3DS Name Address Width Used by
Yes PDN_SPI_CNT 0x101401C0 4 SPI Services
Yes PDN_SHAREDWRAM_32K_DATA<0-7> 0x10141000 1*8
Yes PDN_SHAREDWRAM_32K_CODE<0-7> 0x10141008 1*8
Yes ? 0x10141100 1
Yes ? 0x10141103 1
Yes ? 0x10141104 1
Yes ? 0x10141105 1
Yes ? 0x10141108 1
Yes PDN_WIFI? 0x1014110C 1
Yes ? 0x10141140 1
Yes ? 0x10141141 1
Yes PDN_WIFI_CNT 0x10141180 1
Yes PDN_HID_CNT 0x101411C0 1
Yes ? 0x10141200 4
Yes ? 0x10141FFC 4
Yes PDN_PTM_0 0x10141008 4 PTM Services
Yes PDN_PTM_1 0x1014100C 4 PTM Services
Yes PDN_TWLMODE 0x10141100 2
Yes ? 0x10141104 2
Yes ? 0x10141110 2
Yes ? 0x10141112 2
Yes PDN_CODEC_0 0x10141114 2 CODEC Services
Yes PDN_CODEC_1 0x10141116 2 CODEC Services
Yes PDN_LCD_CNT 0x10141200 1 Boot11 sets/clears bit16, bit0.
Yes PDN_BACKLIGHT_CNT 0x10141202 1
Yes ? 0x10141204 1 Boot11 sets/clears bit0.
Yes ? 0x10141210 1
Yes PDN_CODEC_CNT 0x10141220 1
Yes PDN_CAMERA_CNT 0x10141224 1
Yes ? 0x10141230 1

PDN_SPI_CNT

Bit Description
0 Enable SPI Registers 0x10160000.
1 Enable SPI Registers 0x10142000.
2 Enable SPI Registers 0x10143800.

PDN_SHAREDWRAM_32K_DATA

Used for mapping 32K chunks of shared WRAM for DSP data.

Bits Description
0-1 Master (0=ARM9?, 1=ARM11?, 2 or 3=DSP/data)
2-4 Offset (0..7) (slot 0..7) (LSB of address in 32Kbyte units)
5-6 Not used (0)
7 Enable (0=Disable, 1=Enable)

PDN_SHAREDWRAM_32K_CODE

Used for mapping 32K chunks of shared WRAM for DSP data.

Bits Description
0-1 Master (0=ARM9?, 1=ARM11?, 2 or 3=DSP/code)
2-4 Offset (0..7) (slot 0..7) (LSB of address in 32Kbyte units)
5-6 Not used (0)
7 Enable (0=Disable, 1=Enable)

PDN_WIFI_CNT

Bit0: Enable wifi.

PDN_HID_CNT

Bit0: Enable HID Registers.

PDN_TWLMODE

The very last 3DS-mode register poke the TWL_FIRM Process9 does before it gets switched into TWL-mode, is writing 0x8000 to this register. Before writing this register, TWL Process9 waits for the value of this register to become non-zero. The Process9 code for this runs from ITCM, since switching into TWL-mode includes remapping all ARM9 physical memory.

Writing 0x8000 to here from the ARM9 with NATIVE_FIRM running doesn't seem to do anything, other reg-pokes likely need done first.

PDN_LCD_CNT

This one seems to control the LCD displays?

PDN_BACKLIGHT_CNT

This is the power register used for the LCD backlights.

bit0 = turn on/off LCD backlight, rest = always 0.

PDN_CODEC

The following is the only time the ARM11 CODEC module uses any 0x1EC41XXX registers. In one case CODEC module clears bit1 in register 0x1EC41114, in the other case CODEC module sets bit1 in registers 0x1EC41114 and 0x1EC41116.

PDN_CODEC_CNT

This is the power register used for the PDN CODEC service.

bit0 = unknown, bit1 = turn on/off DSP, rest = always 0.

PDN_CAMERA_CNT

This is the power register used for the PDN camera service.

bit0 = unknown, bit1 = turn on/off cameras, rest = always 0.