simulator: add USB serial input field

movement/movement.c

@@ -25,7 +25,11 @@
 #include <stdio.h>
 #include <string.h>
 #include <limits.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
 #include "watch.h"
+#include "filesystem.h"
 #include "movement.h"
 
 #ifndef MOVEMENT_FIRMWARE
@@ -423,6 +427,32 @@ bool app_loop(void) {
         }
     }
 
+    // if we are plugged into USB, handle the file browser tasks
+    if (watch_is_usb_enabled()) {
+        char line[256] = {0};
+#if __EMSCRIPTEN__
+        // This is a terrible hack; ideally this should be handled deeper in the watch library.
+        // Alas, emscripten treats read() as something that should pop up an input box, so I
+        // wasn't able to implement this over there. I sense that this relates to read() being
+        // the wrong way to read data from USB (like we should be using fgets or something), but
+        // until I untangle that, this will have to do.
+        char *received_data = (char*)EM_ASM_INT({
+            var len = lengthBytesUTF8(tx) + 1;
+            var s = _malloc(len);
+            stringToUTF8(tx, s, len);
+            return s;
+        });
+        memcpy(line, received_data, min(255, strlen(received_data)));
+        free(received_data);
+        EM_ASM({
+            tx = "";
+        });
+#else
+        read(0, line, 256);
+#endif
+        if (strlen(line)) printf(line);
+    }
+
     event.subsecond = 0;
 
     return can_sleep && (movement_state.light_ticks == -1) && !movement_state.is_buzzing;

watch-library/hardware/watch/watch.c

@@ -41,3 +41,7 @@ void SYSTEM_Handler(void) {
 bool watch_is_buzzer_or_led_enabled(void){
     return hri_mclk_get_APBCMASK_TCC0_bit(MCLK);
 }
+
+bool watch_is_usb_enabled(void) {
+    return USB->DEVICE.CTRLA.bit.ENABLE;
+}

watch-library/shared/watch/watch.h

@@ -76,6 +76,10 @@
   */
 bool watch_is_buzzer_or_led_enabled(void);
 
+/** @brief Returns true if USB is enabled.
+  */
+bool watch_is_usb_enabled(void);
+
 /** @brief Reads up to len bytes from the USB serial.
   * @param file ignored, you can pass in 0
   * @param ptr pointer to a buffer of at least len bytes

watch-library/simulator/shell.html

@@ -323,6 +323,9 @@
 
 <button onclick="getLocation()">Set location register (will prompt for access)</button>
 <br>
+<input id="input" style="width: 500px"></input>
+<button id="submit" onclick="sendText()">Send</button>
+<br>
 <textarea id="output" rows="8" style="width: 100%"></textarea>
 
 <script type='text/javascript'>
@@ -365,10 +368,16 @@
   };
   lat = 0;
   lon = 0;
+  tx = "";
   function updateLocation(location) {
     lat = Math.round(location.coords.latitude * 100);
     lon = Math.round(location.coords.longitude * 100);
   }
+  function sendText() {
+    var inputElement = document.getElementById('input');
+    tx = inputElement.value + "\n";
+    inputElement.value = "";
+  }
   function showError(error) {
     switch(error.code) {
       case error.PERMISSION_DENIED:

watch-library/simulator/watch/watch.c

@@ -3,3 +3,7 @@
 bool watch_is_buzzer_or_led_enabled(void) {
     return false;
 }
+
+bool watch_is_usb_enabled(void) {
+    return true;
+}