HID Shared Memory

This page describes the format of the HID shared memory.

The data for each of the below entries(PAD state, circle-pad, touch-screen, etc) is originally written by the HID module at different times per frame.

size: 0x2b0 (System-version v4.4 - 9.0.0-20)

Offset 0x0

Relative offset	Size	Description
0x0	0x8	svcGetSystemTick tick-count output, for when HID module updates entry index0 in the below array.
0x8	0x8	Before the above tick-count field is updated, that value is copied into this field. Therefore, this contains the tick-count for the previous time that entry index0 in the below array was updated by HID module.
0x10	0x4	Index in the following array which was last updated by HID module.
0x18	0x4	3D slider state as f32 (0.0f = completely off, 1.0f = max)
0x1C	0x4	Current PAD state.
0x20	0x4	Raw circle-pad info.
0x28	0x80	Array of 8 entries, where each entry(see below) is 0x10-bytes.

HID module first updates index0, then index1, and so on. When updating the array when the index is already 7, the index is reset to 0.

PAD State

Bit	Description
0	A
1	B
2	Select
3	Start
4	Right
5	Left
6	Up
7	Down
8	R
9	L
10	X
11	Y
12	Inverted value of GPIO bit0.
13	Inverted value of GPIO bit14.
28	Circle pad right (X >= 41)
29	Circle pad left (X <= -41)
30	Circle pad up (Y >= 41)
31	Circle pad down (Y <= -41)

Bit set = button pressed, bit clear = button not pressed. Bit28-31 only apply to the PAD fields in the array entries. Bit28-31 are set by HID module depending on data from a codec command, these are not included with the PAD register itself. Likewise for Bit12-13, except these are set depending on data from a GPIO command, and are likely used with the sharedmem PAD-state field too(this was originally implemented in an old HID module version / initial module version).

Entry format

Relative offset	Size	Description
0x0	0x4	Current PAD state.
0x4	0x4	PAD state for buttons which were pressed(bitmasks which changed from value 0 to value 1) since the last HID update.
0x8	0x4	PAD state for buttons which were released(bitmasks which changed from value 1 to value 0) since the last HID update.
0xC	0x4	This stores circle-pad info: the low s16 is the X coordinate, the high s16 is the Y coordinate. The circle-pad center is approximately 0 for these fields. The range for these fields is approximately: -0x9C(bottom/left) - 0x9C(top/right).

Offset 0xA8

Relative offset	Size	Description
0x0	0x8	svcGetSystemTick tick-count output, for when HID module updates entry index0 in the below array.
0x8	0x8	Before the above tick-count field is updated, that value is copied into this field. Therefore, this contains the tick-count for the previous time that entry index0 in the below array was updated by HID module.
0x10	0x4	Index in the following array which was last updated by HID module.
0x18	0x8	Touch-screen entry, which contains the raw coordinate data prior to being converted to pixel coordinates.
0x20	0x40	8 Touch-screen entries, containing pixel coordinates.

This 0x60-byte region stores state for touch-screen related info. Each touch-screen entry is all-zero when the touch-screen is not being touched.

HID module first updates index0, then index1, and so on. When updating the array when the index is already 7, the index is reset to 0.

Entry format

Relative offset	Size	Description
0x0	0x2	X coordinate.
0x2	0x2	Y coordinate.
0x4	0x4	The u8 at +0 here is 0x0 when this entry doesn't contain any actual data, value 0x1 indicates that this entry contains actual data.

Offset 0x108

Relative offset	Size	Description
0x0	0x8	svcGetSystemTick tick-count output, for when HID module updates entry index0 in the below array.
0x8	0x8	Before the above tick-count field is updated, that value is copied into this field. Therefore, this contains the tick-count for the previous time that entry index0 in the below array was updated by HID module.
0x10	0x4	Index in the following array which was last updated by HID module.
0x18	0x6	Current accelerometer state entry, contains the raw accelerometer output data.
0x20	0x30	Array containing 8 accelerometer entries. Each entry when updated contains accelerometer data converted from the above entry.

The size of this region is 0x50-bytes. This contains the accelerometer state. The data stored under these entries is loaded from MCUHID service commands.

HID module first updates index0, then index1, and so on. When updating the array when the index is already 7, the index is reset to 0.

Entry format

Relative offset	Size	Description
0x0	0x2	s16. X?
0x2	0x2	s16. Y?
0x4	0x2	s16. Z?

Offset 0x158

Relative offset	Size	Description
0x0	0x8	svcGetSystemTick tick-count output, for when HID module updates entry index0 in the below array.
0x8	0x8	Before the above tick-count field is updated, that value is copied into this field. Therefore, this contains the tick-count for the previous time that entry index0 in the below array was updated by HID module.
0x10	0x4	Index in the following array which was last updated by HID module.
0x18	0x6	Current gyroscope state entry.
0x20	0xC0	Array containing 32 gyroscrope entries.

The size of this region is 0xE0-bytes. Initially this contains 0xFF/0x00 bytes. This contains the gyroscope state. The I2C gyroscope device is used for this.

HID module first updates index0, then index1, and so on. When updating the array when the index is already 31, the index is reset to 0.

Entry format

Relative offset	Size	Description
0x0	0x2	s16 X/roll(This the raw byte-swapped data from I2C, for the entry at +0x18 and the array entries).
0x2	0x2	Entry at +0x18: s16 Y/pitch. Array entries: s16 Z/yaw.
0x4	0x2	Entry at +0x18: s16 Z/yaw. Array entries: s16 Y/pitch, from the raw byte-swapped I2C data.

Offset 0x238

Relative offset	Size	Description
0x0	0x8	svcGetSystemTick tick-count output, for when HID module updates entry index0 in the below array.
0x8	0x8	Before the above tick-count field is updated, that value is copied into this field. Therefore, this contains the tick-count for the previous time that entry index0 in the below array was updated by HID module.
0x10	0x4	Index in the following array which was last updated by HID module.
0x18	0x60	Array containing 8 entries, see below.

The size of this region is 0x78-bytes. Initially this contains 0xFF/0x00 bytes. The data stored under these entries is for the DebugPad. I2C deviceid 12 is used for this.

This doesn't have any HID service commands for enabling/disabling this. HID module only updates this state when reading the DebugPad state from hardware via the service command was successful. Since the DebugPad hardware is not available on retail units, this sharedmem section is not updated by HID module on retail units.

HID module first updates index0, then index1, and so on. When updating the array when the index is already 7, the index is reset to 0.

Entry format

Relative offset	Size	Description
0x0	0x2	Keys held
0x2	0x2	Keys just pressed
0x4	0x2	Keys just released
0x6	0x1	Left Stick X (range roughly -32 to +31)
0x7	0x1	Left Stick Y (range roughly -32 to +31)
0x8	0x1	Right Stick X (range roughly -16 to +15)
0x9	0x1	Right Stick Y (range roughly -16 to +15)
0xA	0x2	Padding, not written by HID module.

Note: there is code in hid sysmodule where holding +, -, DPAD Left, and A will recallibrate the sticks to zero.