Old3DS Name Address Width
Yes GPIO1_DATA 0x10147000 1
Yes GPIO2_DATA 0x10147010 1
Yes GPIO2_DIR 0x10147011 1
Yes GPIO2_INTCFG 0x10147012 1
Yes GPIO2_INTEN 0x10147013 1
Yes GPIO2_DATA2 0x10147014 2
Yes GPIO3_DATA 0x10147020 2
Yes GPIO3_DIR 0x10147022 2
Yes GPIO3_INTCFG 0x10147024 2
Yes GPIO3_INTEN 0x10147026 2
Yes GPIO3_DATA2 0x10147028 2

Legacy RTCEdit

Name Address Width Description
RTC_CNT 0x10147100 2 Control register
RTC_REG_STAT1 0x10147110 1 Rtc status register 1 (command 0). Bitswapped
RTC_REG_STAT2 0x10147111 1 Rtc status register 2 (command 1). Bitswapped
RTC_REG_CLKADJ 0x10147112 1 Rtc clock adjustment register (command 6). Bitswapped
RTC_REG_FREE 0x10147113 1 The free general purpose rtc register (command 7). Bitswapped
RTC_REG_TIME1 0x10147120 4 Byte-wise bit-swapped (bit7 is bit0, etc.) BCD RTC (byte0 = seconds, byte1 = minutes, byte2 = hours, byte3 = day of week)
RTC_REG_TIME2 0x10147124 4 (3?) Day, month and year all byte-wise bit-swapped
RTC_REG_ALRMTIM1 0x10147130 4 (3?) Rtc alarm time register 1 (command 4). Byte-wise bit-swapped
RTC_REG_ALRMTIM2 0x10147134 4 (3?) Rtc alarm time register 2 (command 5). Byte-wise bit-swapped
RTC_REG_COUNT 0x10147140 4 (3?) Rtc dsi counter register (ex command 0). Byte-wise bit-swapped
RTC_REG_FOUT1 0x10147150 1 Rtc dsi fout register 1 (ex command 1). Bitswapped
RTC_REG_FOUT2 0x10147151 1 Rtc dsi fout register 2 (ex command 2). Bitswapped
RTC_REG_ALRMDAT1 0x10147160 4 (3?) Rtc dsi alarm date register 1 (ex command 4). Byte-wise bit-swapped
RTC_REG_ALRMDAT2 0x10147164 4 (3?) Rtc dsi alarm date register 2 (ex command 5). Byte-wise bit-swapped



GPIO pinsEdit

Only GPIO2 and GPIO3 pins have their interrupts configurable. Active low pins should be configured as "falling edge", and output ports shouldn't have interrupts enabled at all.

GPIO Services bitmasks use this table, in that order:

Bit IRQ ID Description
0 ? Debug button (?) (active-low)
1 0x63 (falling edge) Touch Screen (active low, 0 = screen pressed)
2 0x60 (falling edge)

0x62 (rising edge)

Shell closed
0 0x64 Headphones inserted
1 0x66 TWL depop circuit (?) (active-low)
DATA2.0 - WiFi mode/freq. select (0 = CTR, 1 = MP (DS WiFi))
0 0x68 C-stick interrupt
1 0x69 IrDA interrupt (active-low)
2 0x6A Gyro interrupt
3 0x6B C-stick "stop" (output)
4 0x6C IrDA TX-RC (output)
5 0x6D IrDA RXD (active-low)
6 0x6E NFC output1 (?)
7 0x6F NFC output2 (?)
8 0x70 Headphones button/half-inserted (active-low)
9 0x71 MCU interrupt
10 0x72 NFC interrupt (?)
11 0x73 QTM output (?)
DATA2.0 - WiFi enable


Pin values, one bit per pin.


Pin directions for GPIO2 and GPIO3, one bit per pin.

Value Description
0 Input
1 Output


Interrupt configuration for GPIO2 and GPIO3 pins (not the extra ones), one bit per pin.

Value Description
0 Falling edge
1 Rising edge


Interrupt enable bits for GPIO2 and GPIO3 pins (not the extra ones), one bit per pin.

Value Description
0 Interrupt disabled
1 Interrupt enabled


Extra pins for GPIO2 and GPIO3 (one bit each). These two pins, in total, are not bound to any IRQ and are not configurable.

Default valuesEdit

After bootrom initialization, these are the values of the registers:

Address Value
0x10147000 0x0003
0x10147010 0x00000002
0x10147014 0x0000
0x10147020 0x00000DFB
0x10147024 0x00000000
0x10147028 0x0000

Legacy RTCEdit

RTC_CNT (0x10147100)Edit

Bit Description
0 Latch STAT1
1 Latch STAT2
2 Latch CLKADJ
3 Latch FREE
4 Latch TIME
5 Latch ALRMTIM1
6 Latch ALRMTIM2
7 Latch COUNT
8 Latch FOUT1
9 Latch FOUT2
10 Latch ALRMDAT1
11 Latch ALRMDAT2
12 ARM7 Busy? This may be chipselect
13 ARM7 write command received? (writing 1 clears it seems)
14 ARM7 read command recieved? (writing 1 clears it seems)
15 DS SIO SI pin (rtc irq pin)