Initial commit

switch-pico.cpp

@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include "bsp/board.h"
+#include "hardware/uart.h"
+#include "pico/stdlib.h"
+#include "tusb.h"
+#include "switch_pro_driver.h"
+
+// UART1 is reserved for external input frames from the host PC.
+#define UART_ID uart1
+#define BAUD_RATE 115200
+#define UART_TX_PIN 4
+#define UART_RX_PIN 5
+
+static void init_uart_input() {
+    uart_init(UART_ID, BAUD_RATE);
+    gpio_set_function(UART_TX_PIN, GPIO_FUNC_UART);
+    gpio_set_function(UART_RX_PIN, GPIO_FUNC_UART);
+    uart_set_format(UART_ID, 8, 1, UART_PARITY_NONE);
+}
+
+static SwitchInputState neutral_input() {
+    SwitchInputState state{};
+    state.lx = SWITCH_PRO_JOYSTICK_MID;
+    state.ly = SWITCH_PRO_JOYSTICK_MID;
+    state.rx = SWITCH_PRO_JOYSTICK_MID;
+    state.ry = SWITCH_PRO_JOYSTICK_MID;
+    return state;
+}
+
+// Consume UART bytes and forward complete frames to the Switch Pro driver.
+static void poll_uart_frames() {
+    static uint8_t buffer[8];
+    static uint8_t index = 0;
+    static absolute_time_t last_byte_time = {0};
+    static bool has_last_byte = false;
+
+    while (uart_is_readable(UART_ID)) {
+        uint8_t byte = uart_getc(UART_ID);
+
+        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
+        }
+        last_byte_time = get_absolute_time();
+        has_last_byte = true;
+
+        if (index == 0) {
+            if (byte != 0xAA) {
+                continue; // wait for start-of-frame marker
+            }
+        }
+
+        buffer[index++] = byte;
+        if (index >= sizeof(buffer)) {
+            switch_pro_apply_uart_packet(buffer, sizeof(buffer));
+            index = 0;
+        }
+    }
+}
+
+int main() {
+    board_init();
+    stdio_init_all();
+
+    init_uart_input();
+
+    tusb_init();
+    switch_pro_init();
+    switch_pro_set_input(neutral_input());
+
+    while (true) {
+        tud_task();          // USB device tasks
+        poll_uart_frames();  // Pull controller state from UART1
+        switch_pro_task();   // Push state to the Switch host
+    }
+}