jyapayne/switch-pico
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feat(firmware): add IMU data structures and UART v2 parser

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- Add SwitchImuSample struct and IMU fields to SwitchInputState
- Add fill_imu_report_data() to pack samples into imuData[36]
- Rewrite switch_pro_apply_uart_packet() for v2 with checksum validation
- Enlarge poll_uart_frames() buffer to 64 bytes for variable-length frames
- Clear imu_sample_count after each USB report send (prevent stale IMU)
This commit is contained in:
Joey Yakimowich-Payne 2026-03-16 11:50:32 -06:00
commit 4501528371
3 changed files with 135 additions and 28 deletions
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40
switch-pico.cpp
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@ -61,11 +61,13 @@ static void on_rumble_from_switch(const uint8_t rumble[8]) {
}
// Consume UART bytes and forward complete frames to the Switch Pro driver.
static void poll_uart_frames() {
static uint8_t buffer[8];
static bool poll_uart_frames() {
static uint8_t buffer[64];
static uint8_t index = 0;
static uint8_t expected_len = 0;
static absolute_time_t last_byte_time = {0};
static bool has_last_byte = false;
bool new_data = false;
while (uart_is_readable(UART_ID)) {
uint8_t byte = uart_getc(UART_ID);
@ -73,6 +75,7 @@ static void poll_uart_frames() {
uint64_t now = to_ms_since_boot(get_absolute_time());
if (has_last_byte && (now - to_ms_since_boot(last_byte_time)) > 20) {
index = 0; // stale data, restart frame
expected_len = 0;
}
last_byte_time = get_absolute_time();
has_last_byte = true;
@ -83,11 +86,26 @@ static void poll_uart_frames() {
}
}
buffer[index++] = byte;
if (index >= sizeof(buffer)) {
index = 0;
expected_len = 0;
}
buffer[index++] = byte;
if (index == 3) {
expected_len = static_cast<uint8_t>(buffer[2] + 4u);
if (expected_len < 12 || expected_len > sizeof(buffer)) {
index = 0;
expected_len = 0;
continue;
}
}
if (expected_len > 0 && index >= expected_len) {
SwitchInputState parsed{};
if (switch_pro_apply_uart_packet(buffer, sizeof(buffer), &parsed)) {
if (switch_pro_apply_uart_packet(buffer, expected_len, &parsed)) {
g_user_state = parsed;
new_data = true;
LOG_PRINTF("[UART] packet buttons=0x%04x hat=%u lx=%u ly=%u rx=%u ry=%u\n",
(parsed.button_a ? SWITCH_PRO_MASK_A : 0) |
(parsed.button_b ? SWITCH_PRO_MASK_B : 0) |
@ -104,14 +122,17 @@ static void poll_uart_frames() {
(parsed.button_l3 ? SWITCH_PRO_MASK_L3 : 0) |
(parsed.button_r3 ? SWITCH_PRO_MASK_R3 : 0),
parsed.dpad_up ? SWITCH_PRO_HAT_UP :
parsed.dpad_down ? SWITCH_PRO_HAT_DOWN :
parsed.dpad_left ? SWITCH_PRO_HAT_LEFT :
parsed.dpad_right ? SWITCH_PRO_HAT_RIGHT : SWITCH_PRO_HAT_NOTHING,
parsed.lx >> 8, parsed.ly >> 8, parsed.rx >> 8, parsed.ry >> 8);
parsed.dpad_down ? SWITCH_PRO_HAT_DOWN :
parsed.dpad_left ? SWITCH_PRO_HAT_LEFT :
parsed.dpad_right ? SWITCH_PRO_HAT_RIGHT : SWITCH_PRO_HAT_NOTHING,
parsed.lx >> 8, parsed.ly >> 8, parsed.rx >> 8, parsed.ry >> 8);
}
index = 0;
expected_len = 0;
}
}
return new_data;
}
static void log_usb_state() {
@ -146,7 +167,8 @@ int main() {
while (true) {
tud_task(); // USB device tasks
poll_uart_frames(); // Pull controller state from UART1
bool new_data = poll_uart_frames(); // Pull controller state from UART1
(void)new_data;
SwitchInputState state = g_user_state;
switch_pro_set_input(state);
switch_pro_task(); // Push state to the Switch host