Overview

Old3DS A9/A11 Category Physaddr Used by Comments
Yes A9 CONFIG Registers 0x10000000 Boot9, Process9
Yes A9 IRQ Registers 0x10001000 Boot9, Process9, Kernel9 ARM9 Interrupt Masking
Yes A9 NDMA Registers 0x10002000 Boot9, Process9 DMA Engine
Yes A9 TIMER Registers 0x10003000 Boot9, Process9
Yes A9 CTRCARD Registers 0x10004000 / 0x10005000 Process9
Yes A9 EMMC Registers 0x10006000 / 0x10007000 Boot9, Process9 0x10007000 is normally not enabled on retail, all-zeros when read.
Yes A9 PXI Registers 0x10008000 Boot9, Process9
Yes A9 AES Registers 0x10009000 Boot9, Process9
Yes A9 SHA Registers 0x1000A000 Boot9, Process9
Yes A9 RSA Registers 0x1000B000 Boot9, Process9
Yes A9 XDMA Registers 0x1000C000 Boot9, Kernel9 CoreLink™ DMA-330 (single-channel).
Yes A9 SPICARD Registers 0x1000D800 Process9
Yes ? CONFIG Registers 0x10010000 Process9
Yes ? PRNG Registers 0x10011000 Process9 Used as entropy-source for seeding random number generators.
Yes ? OTP Registers 0x10012000 Kernel9, NewKernel9Loader Top secret.
Yes ? ARM7 Registers 0x10018000 TwlProcess9 Used to setup the ARM7 core for AGB/TWL
Yes ? ? 0x10100000 ? ?
Yes A11/A9 HASH Registers 0x10101000 Filesystem services
Yes A11/A9 Camera Registers 0x10102000 Camera Services y2r
Yes A11/A9 CSND Registers / DSP Registers 0x10103000 TwlBg, Codec Services, CSND Services, DSP Services Sound hardware. For DSP regs, see the "DSi XpertTeak" section in no$gba help.
Yes A11/A9 LGYFB0 0x10110000 TwlBg IO registers used to access legacy output framebuffer, as well as configure the upscaling filter.
Yes A11/A9 LGYFB1 0x10111000 TwlBg IO registers used to access legacy output framebuffer, as well as configure the upscaling filter.
Yes A11/A9 Camera Registers 0x10120000 Camera Services
Yes A11/A9 Camera Registers 0x10121000 Camera Services Mirror of 0x10120000?
Yes A11/A9 ? 0x10122000 NWM Services WIFI?
Yes A11/A9 ? 0x10123000 NWM Services WIFI?
No A11/A9 MVD Registers 0x10130000 MVD Services
No A11/A9 MVD Registers 0x10131000 MVD Services
No A11/A9 MVD Registers 0x10132000 MVD Services
Yes A11/A9 PDN Registers 0x10140000 Process9, Boot11, Kernel11, TwlBg, DSP Services, NWM Services, SPI Services Power management.
Yes A11/A9 PDN Registers 0x10141000 Process9, Boot11, Kernel11, TwlBg, Codec Services, NWM Services, SPI Services, PDN Services Power management
Yes A11/A9 SPI Registers 0x10142000 TwlBg, SPI Services
Yes A11/A9 SPI Registers 0x10143000 TwlBg, dmnt Module Debugger related?
Yes A11/A9 I2C Registers 0x10144000 Boot11, Kernel11, TwlBg, I2C Services
Yes A11/A9 CODEC Registers 0x10145000 TwlBg, Codec Services
Yes A11/A9 HID Registers 0x10146000 Boot11, Kernel11, TwlBg, HID Services, dlp Services See PAD.
Yes A11/A9 GPIO Registers 0x10147000 Boot11, TwlBg, GPIO Services, DSP Services(v0)
Yes A11/A9 I2C Registers 0x10148000 TwlBg, I2C Services
Yes A11/A9 SPI Registers 0x10160000 Boot9, TwlBg, SPI Services
Yes A11/A9 I2C Registers 0x10161000 Boot11, TwlBg, I2C Services See no$gba help for some clues maybe.
Yes A11/A9 MIC Registers 0x10162000 MIC Services
Yes A11/A9 PXI Registers 0x10163000 Boot11, Kernel11, TwlBg, PXI Services
Yes A11/A9 NTRCARD Registers 0x10164000 Boot9, Process9
Yes A11/A9 MP Registers 0x10165000 MP Services
Yes A11/A9 MP Registers 0x10170000 MP Services NTR WIFI Registers, see GBATek.
Yes A11/A9 MP Registers 0x10171000 MP Services NTR WIFI Registers (mirror)
Yes A11/A9 ? 0x10172000 ? NTR WIFI Unused?
Yes A11/A9 ? 0x10173000 ? NTR WIFI Unused?
Yes A11/A9 MP Registers 0x10174000 MP Services NTR WIFI RAM
Yes A11/A9 MP Registers 0x10175000 ? NTR WIFI RAM
Yes A11/A9 MP Registers 0x10176000 ? NTR WIFI Registers (mirror)
Yes A11/A9 MP Registers 0x10177000 ? NTR WIFI Registers (mirror)
Yes A11/A9 MP Registers 0x10178000 - 0x10180000 MP Services NTR WIFI WS1 Region
Yes A11 CDMA 0x10200000 Boot11, Kernel11 CoreLink™ DMA-330. Not used on New3DS.
Yes A11 ? 0x10201000
Yes A11 LCD Registers 0x10202000 TwlBg, Kernel11, GSP Services
Yes A11 DSP Registers 0x10203000 DSP Services
Yes A11 ? 0x10204000
No A11 CDMA 0x10206000 NewKernel11 CDMA was moved here on New 3DS. CoreLink™ DMA-330.
No A11 MVD Registers 0x10207000 MVD Services New 3DS only?
Yes A11 AXI 0x1020F000 TwlBg, GSP Services CoreLink™ NIC-301 r1p0.
Yes A11 MIRROR 0x10300000-0x10400000 Mirror of 0x10100000-0x10200000 (faster bus?), CDMA wants these addresses
Yes A11 GPU Registers 0x10400000 Boot11, Kernel11, GSP Services

IO registers starting at physical address 0x10200000 are not accessible from the ARM9 (which includes all LCD/GPU registers). It seems IO registers below physical address 0x10100000 are not accessible from the ARM11 bus.

ARM11 kernel virtual address mappings for these registers varies for different builds. For ARM11 user mode applications you have:

physaddr = virtaddr - 0x1EC00000 + 0x10100000