pbio/platform/nxt: Don't block until user connects RFCOMM.

Until now, pbio did not start until a Bluetooth classic connection was established. This makes development cumbersome since connecting is required every time.

Now the connection is accepted in the background while pbio is running. This is expected to go away once USB is enabled.

Author: laurensvalk

bricks/nxt/mphalport.c

@@ -47,9 +47,15 @@ uintptr_t mp_hal_stdio_poll(uintptr_t poll_flags) {
     return ret;
 }
 
+extern bool nx_bt_is_ready(void);
+
 // Receive single character
 int mp_hal_stdin_rx_chr(void) {
 
+    while (!nx_bt_is_ready()) {
+        MICROPY_EVENT_POLL_HOOK
+    }
+
     uint8_t rx_char;
 
     // Start reading again for next char
@@ -66,6 +72,10 @@ int mp_hal_stdin_rx_chr(void) {
 // Send string of given length
 mp_uint_t mp_hal_stdout_tx_strn(const char *str, size_t len) {
 
+    while (!nx_bt_is_ready()) {
+        MICROPY_EVENT_POLL_HOOK
+    }
+
     // Nothing to do if disconnected or empty data
     if (!nx_bt_stream_opened() || len == 0) {
         return len;

lib/pbio/platform/nxt/platform.c

@@ -5,6 +5,7 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <string.h>
 
 #include <pbdrv/reset.h>
 #include <pbio/button.h>
@@ -28,16 +29,12 @@
 #include <nxos/drivers/systick.h>
 #include <nxos/interrupts.h>
 
-// FIXME: Needs to use a process very similar to pbsys/bluetooth
-static bool bluetooth_connect(void) {
-
-    int port_handle = -1;
-    int connection_handle = -1;
+const char *pin = "1234";
 
+static void legacy_bluetooth_init_blocking(void) {
     nx_bt_init();
 
     char *name = "Pybricks NXT";
-    char *pin = "1234";
     nx_bt_set_friendly_name(name);
 
     nx_display_string("Bluetooth name:\n");
@@ -56,39 +53,63 @@ static bool bluetooth_connect(void) {
 
     nx_bt_set_discoverable(true);
 
-    port_handle = nx_bt_open_port();
-    (void)port_handle;
+    nx_bt_open_port();
+}
+
+// REVISIT: This process waits for the user to connect to the NXT brick with
+// Bluetooth classic (RFCOMM). This allows basic I/O until proper Pybricks USB
+// or Bluetooth classic solutions are implemented. Then this process will be
+// removed.
+static pbio_os_process_t legacy_bluetooth_connect_process;
+
+static pbio_error_t legacy_bluetooth_connect_process_thread(pbio_os_state_t *state, void *context) {
+
+    PBIO_OS_ASYNC_BEGIN(state);
+
+    static pbio_os_timer_t timer;
+
+    static int connection_handle = -1;
 
     while (!nx_bt_stream_opened()) {
-        if (pbsys_status_test(PBIO_PYBRICKS_STATUS_SHUTDOWN_REQUEST)) {
-            return false;
-        }
 
         if (nx_bt_has_dev_waiting_for_pin()) {
-            nx_bt_send_pin(pin);
+            nx_bt_send_pin((char *)pin);
             nx_display_string("Please enter pin.\n");
         } else if (nx_bt_connection_pending()) {
             nx_display_string("Connecting ...\n");
             nx_bt_accept_connection(true);
 
             while ((connection_handle = nx_bt_connection_established()) < 0) {
-                if (pbsys_status_test(PBIO_PYBRICKS_STATUS_SHUTDOWN_REQUEST)) {
-                    return false;
-                }
-
-                pbio_os_run_processes_once();
+                PBIO_OS_AWAIT_MS(state, &timer, 2);
             }
 
             nx_bt_stream_open(connection_handle);
         }
 
-        pbio_os_run_processes_once();
+        PBIO_OS_AWAIT_MS(state, &timer, 100);
     }
 
     nx_display_clear();
     nx_display_cursor_set_pos(0, 0);
 
-    return true;
+    nx_display_string("RFCOMM ready.\n");
+    nx_display_string("Press a key.\n");
+
+    // Receive one character to get going.
+    static uint8_t flush_buf[1];
+    nx_bt_stream_read(flush_buf, sizeof(flush_buf));
+
+    while (nx_bt_stream_data_read() != sizeof(flush_buf)) {
+        PBIO_OS_AWAIT_MS(state, &timer, 2);
+    }
+
+    nx_display_string("Let's code!\n");
+
+    PBIO_OS_ASYNC_END(PBIO_SUCCESS);
+}
+
+bool nx_bt_is_ready(void) {
+    return legacy_bluetooth_connect_process.err == PBIO_SUCCESS;
 }
 
 // Called from assembly code in startup.S
@@ -119,24 +140,9 @@ void SystemInit(void) {
     /* Delay a little post-init, to let all the drivers settle down. */
     nx_systick_wait_ms(100);
 
-    // REVISIT: Integrate via pbsys/bluetooth
-
-    // Accept incoming serial connection and get ready to read first byte.
-    if (bluetooth_connect()) {
-        // Receive one character to get going...
-        uint8_t flush_buf[1];
-        nx_display_string("Press a key.\n");
-        nx_bt_stream_read(flush_buf, sizeof(flush_buf));
+    // Blocking Bluetooth setup, then await user connection without blocking,
+    // allowing pbio processes to start even if nothing is connected.
+    legacy_bluetooth_init_blocking();
+    pbio_os_process_start(&legacy_bluetooth_connect_process, legacy_bluetooth_connect_process_thread, NULL);
 
-        while (nx_bt_stream_data_read() != sizeof(flush_buf)) {
-            if (pbsys_status_test(PBIO_PYBRICKS_STATUS_SHUTDOWN_REQUEST)) {
-                goto out;
-            }
-
-            pbio_os_run_processes_once();
-        }
-
-        nx_display_string("Connected. REPL.\n");
-    out:;
-    }
 }