CONFIG11 Registers

Registers

Old3DS	Name	Address	Width	Used by
Yes	CFG11_SHAREDWRAM_32K_DATA<0-7>	0x10140000	1*8	Boot11, Process9, DSP Services
Yes	CFG11_SHAREDWRAM_32K_CODE<0-7>	0x10140008	1*8	Boot11, Process9, DSP Services
Yes	?	0x10140100	2
Yes	?	0x10140102	2
Yes	CFG11_FIQ_CNT	0x10140104	1	Kernel11.
Yes	?	0x10140105	1	Kernel11.
Yes	Related to HID_?	0x10140108	2	TwlBg
Yes	Related to HID_?	0x1014010C	2	TwlBg
Yes	CFG11_GPUPROT	0x10140140	4	Kernel11
Yes	CFG11_WIFICNT	0x10140180	1	TwlBg, NWM Services
Yes	CFG11_SPI_CNT	0x101401C0	2	SPI Services, TwlBg
Yes	?	0x10140200	4
No	Clock related?	0x10140400	1	NewKernel11
No	Clock related?	0x10140410	4	NewKernel11
No	CFG11_BOOTROM_OVERLAY_CNT	0x10140420	1	NewKernel11
No	CFG11_BOOTROM_OVERLAY_VAL	0x10140424	4	NewKernel11
No	?	0x10140428	4
Yes	CFG11_SOCINFO	0x10140FFC	2	Boot11, Kernel11
Yes	CFG11_GPU_STATUS	0x10141000	2	Kernel11, TwlBg
Yes	CFG11_PTM_0	0x10141008	4	PTM Services, PDN Services
Yes	CFG11_PTM_1	0x1014100C	4	PTM Services, TwlBg, PDN Services
Yes	LGY_MODE	0x10141100	2	TwlProcess9, TwlBg
Yes	LGY_SLEEP	0x10141104	2	TwlBg
Yes	LGY_IRQ_?	0x10141108	2	TwlBg
Yes	LGY_PADCNT	0x1014110A	2	TwlBg
Yes	CFG11_WIFIUNK	0x1014110C	1	NWM Services
Yes	CFG11_TWLAGB_HIDEMU_MASK	0x10141110	2	TwlBg
Yes	CFG11_TWLAGB_HIDEMU_PAD	0x10141112	2	TwlBg
Yes	CFG11_CODEC_0	0x10141114	2	Codec Services, TwlBg
Yes	CFG11_CODEC_1	0x10141116	2	Codec Services, TwlBg
Yes	?	0x10141118	1	TwlBg
Yes	?	0x10141119	1	TwlBg
Yes	?	0x10141120	1	TwlBg
Yes	CFG11_GPU_CNT	0x10141200	4	Boot11, Kernel11, PDN Services, TwlBg
Yes	CFG11_GPU_CNT2	0x10141204	4	Boot11, Kernel11, TwlBg
Yes	CFG11_FCRAM_CNT	0x10141210	2	Kernel11, TwlBg
Yes	CFG11_CODEC_CNT	0x10141220	1	Boot11, TwlBg, PDN Services
Yes	CFG11_CAMERA_CNT	0x10141224	1	PDN Services
Yes	CFG11_DSP_CNT	0x10141230	1	Process9, PDN Services
No	CFG11_MPCORE_CLKCNT	0x10141300	2	NewKernel11
No	CFG11_MPCORE_CNT	0x10141304	2	NewKernel11
No	CFG11_MPCORE_BOOTCNT<0-3>	0x10141310	1*4	NewKernel11

CFG11_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)

CFG11_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)

CFG11_FIQ_CNT

Writing bit1 to this register disables FIQ interrupts.

This bit is set upon receipt of a FIQ interrupt and when svcUnbindInterrupt is called on the FIQ-abstraction software interrupt for the current core. It is cleared when binding that software interrupt to an event and just before that event is signaled.

CFG11_SPI_CNT

When the corresponding bit is 0, the bus has to be accessed using the DS SPI registers. Otherwise it has to be accessed using the 3DS SPI registers.

Bit	Description
0	Enable SPI Registers 0x10160800.
1	Enable SPI Registers 0x10142800.
2	Enable SPI Registers 0x10143800.

CFG11_BOOTROM_OVERLAY_CNT

Bit0: Enable bootrom overlay functionality.

CFG11_BOOTROM_OVERLAY_VAL

The 32-bit value to overlay data-reads to bootrom with. See CFG11_MPCORE_BOOTCNT.

CFG11_SOCINFO

Read-only register.

Bits	Description	Used by
0	1 on both Old3DS and New3DS.	Boot11
1	1 on New3DS.	Kernel11
2	Clock modifier: if set, use a 3x multiplier, otherwise 2x	Kernel11

CFG11_MPCORE_CLKCNT

This is used for configuring the New3DS ARM11 CPU clock-rate. This register is New3DS-only: reading from here on Old3DS always returns all-zeros even when one tried writing data here prior to the read.

Bits	Description
0	Enable clock multiplier? This must be set to 1 before writing a non-zero value to bit1-2, otherwise freeze. This enables the New 3DS FCRAM extension.
1-2	Clock multiplier (0=1x, 1=2x, 2=3x, 3=hang)
15	Busy

svcKernelSetState type10, only implemented on New3DS, uses this register. That code writes the following values to this register, depending on the input Param0 bit0 state, and the state of CFG11_SOCINFO:

Register value	Higher-clockrate bit set in svcKernelSetState Param0	CFG11_SOCINFO bit2 set	MPCore timer/watchdog prescaler value, prior to subtracting it by 0x1 when writing it into hw/state	Clock-rate multiplier	Description
0x01	No	Yes	0x01	1x	268MHz
0x02	No	No	0x01	1x	268MHz
0x05	Yes	Yes	0x03	3x	804MHz
0x03	Yes	No	0x02	2x	536MHz (tested on New3DS)

Note that the above CFG11_SOCINFO bit is 1 on New3DS, and 0 on Old3DS. Since this SVC is only available with the New3DS ARM11-kernel, the only additional available clock-rate is 804MHz when running on New3DS(with official kernel code).

The following register value(s) were tested on New3DS by patching the kernel:

• 0x00: Entire system hangs.
• 0x02: Entire system hangs.
• 0x03: ARM11 runs at 536MHz.
• 0x04: Entire system hangs.
• 0x06: Entire system hangs.
• 0x07: Same result as 0x05.
• 0x08: Entire system hangs.
• 0x09: Entire system hangs.
• 0x0A: Entire system hangs.
• 0x0B: Same result as 0x03.
• 0x0C: Entire system hangs.
• 0x0D: Same result as 0x05.
• 0x0E: Entire system hangs.
• 0x0F: Same result as 0x05.
• 0x1F, 0x2F, 0x4F, 0x8F, 0xFF: Same result as 0x05.

CFG11_MPCORE_CNT

Bits	Description
0	?
8	?

Kernel11 sets this to 0x101 when bit 2 in CFG11_SOCINFO is set otherwise 1.

CFG11_MPCORE_BOOTCNT<0-3>

Bits	Description
0	Enable bootrom instruction overlay, maybe? This bit is only writable for core2 and core3.
1	Enable bootrom data overlay. This bit is only writable for core2 and core3.
4	Has core booted maybe?
5	Always 1?

The normal ARM11 bootrom checks cpuid and hangs if cpuid >= 2. This is a problem when booting the 2 additional New3DS ARM11 MPCores. NewKernel11 solves this by using a hardware feature to overlay the bootrom with a configurable branch to a kernel function. This overlay feature was added with the New3DS.

Bit1 in register above enables a bootrom data-override for physical addresses 0xFFFF0000-0xFFFF1000 and 0x10000-0x11000. All _data reads_ made to those regions now read the 32-bit value provided in CFG11_BOOTROM_OVERLAY_VAL.

Bit0 enables a bootrom instruction-overlay which means that _instruction reads_ made to the bootrom region are overridden. We have not been able to dump what instructions are actually placed at bootrom by this switch (because reading the area only yields data-reads). Jumping randomly into the 0xFFFF0000-0xFFFF1000 region works fine and jumps to the value provided by the data overlay CFG11_BOOTROM_OVERLAY_VAL. Thus we may predict that the entire bootrom region is filled by: ldr pc, [pc]

Or equivalent. However, jumping to some high addresses such as 0xFFFF0FF0+ will crash the core. This may be explained by prefetching in the ARM pipeline, and might help us identify what instructions are placed by the instruction-overlay.

CFG11_GPUPROT

Old3DS	Bits	Description
Yes	3-0	Old FCRAM DMA cutoff size, 0 = no protection.
No	7-4	New FCRAM DMA cutoff size, 0 = no protection.
Yes	8	AXIWRAM protection, 0 = accessible.
No	10-9	QTM DMA cutoff size
Yes	31-11	Zeroes

For the old FCRAM DMA cutoff, it protects starting from 0x28000000-(0x800000*x) until end of FCRAM. There is no way to protect the first 0x800000-bytes.

For the new FCRAM DMA cutoff, it protects starting from 0x30000000-(0x800000*x) until end of FCRAM. When the old FCRAM cutoff is set to non-zero, the first 0x800000-bytes bytes of new FCRAM are protected.

On New3DS the old+new FCRAM cutoff can be used at the same time, however this isn't done officially.

For the QTM DMA cutoff, it protects starting from 0x1F400000-(0x100000*x) until end of QTM mem.

On cold boot this reg is set to 0.

When this register is set to value 0, the GPU can access the entire FCRAM, AXIWRAM, and on New3DS all QTM-mem.

Initialized during kernel boot, and used with SVC 0x59 which was implemented with v11.3.

CFG11_WIFICNT

Old3DS	Bits	Description
Yes	0	Enable wifi subsystem

LGY_MODE

Bits	Description
0-1	Read only legacy mode set on reg 0x10018000.
2-14	Unused.
15	1 = enable legacy mode.

To boot into DSi or GBA mode first set register 0x10018000 to the desired mode and setup LgyFb. Then disable FCRAM by clearing bit 0 in reg 0x10201000, writing 0 to CFG11_FCRAM_CNT followed by 1 and waiting for bit 3 to clear.

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 ARM7 to change the value of this register. The Process9 code for this runs from ITCM, since switching into TWL-mode includes remapping all ARM9 physical memory.

LGY_SLEEP

Bits	Description
0	Write 1 to wakeup GBA mode.
1	Sleep state/ack. 1 when GBA mode entered sleep. Write 1 to ack.
2	?
3-14	Unused.
15	1 = IRQ enable (IRQ 0x59)

When a GBA game enters sleep mode and bit 15 is 1, IRQ 0x59 fires and bit 1 is set. Bit 1 must be acknowledged/written together with bit 0 otherwise GBA mode wakes up from sleep early sometimes.

LGY_IRQ_?

Bitfield.

LGY_PADCNT

Also named "KEYCNT" on certain other DS(i)/GBA documentaions. The value of this register is copied to HID_? when GBA mode enters sleep.

CFG11_WIFIUNK

Old3DS	Bits	Description
Yes	4	Wifi-related? Set to 1 very early in NWM-module.

CFG11_TWLAGB_HIDEMU_MASK

Set bits will use the corresponding values from CFG11_TWLAGB_HIDEMU_PAD instead of allowing the hardware to read it from HID_PAD.

This is set to 0x1FFF (all buttons and the debug key) and CFG11_TWLAGB_HIDEMU_PAD is set to 0 when the "Close this software and return to HOME Menu?" dialog is shown to prevent the button presses from propagating to the DS/GBA CPU.

CFG11_TWLAGB_HIDEMU_PAD

Works the same way as HID_PAD, but the values set here are only replaced in the HID_PAD seen by the DS/GBA CPU when the corresponding bits in CFG11_TWLAGB_HIDEMU_MASK are set.

CFG11_GPU_CNT

Bits	Description
0	Unknown reset. 0 = reset.
1	PSC block reset? 0 = reset.
2	Geoshader block reset? 0 = reset.
3	Rasterization block reset? 0 = reset.
4	PPF block reset. 0 = reset.
5	PDC block reset? 0 = reset.
6	PDC related reset. 0 = reset.
7-15	Unused.
16	Clock enable for all blocks. 1 = enable.

Bit0: main (?) nRESET (active low), unset to reset (when not on reset, external GPU registers at 0x10400000+ are enabled). When this is unset VRAM is not accessible and triggers exceptions.

PDN uses a 12 ARM11 cycle delay to deassert reset.

CFG11_GPU_CNT2

Bit0: Power on GPU?

CFG11_FCRAM_CNT

Bits	Description
0	Reset. 0 = reset.
1	Enable something. 1 = enable.
2	Acknowledge? Gets set or unset when toggling bit 1.

Twl-/AgbBg use this to disable FCRAM for the GBA rom in GBA mode or DSi main RAM in DSi mode. Agb-/TwlBg clears bit 0 in reg 0x10201000 before touching this reg.

CFG11_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.

CFG11_CODEC_CNT

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

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

CFG11_CAMERA_CNT

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

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

CFG11_DSP_CNT

This is the power register used for the PDN Services DSP service.

bit0: NRESET (active low). Unset to reset/hold reset. bit1: enable bit.

PDN services holds reset for 0x30 Arm11 cycles.