commit ddc028fe18414ceeebfb2b491bd8fcba3acb9366
author Jonathan Bell <jonathan@raspberrypi.com> Mon Mar 18 15:52:28 2024 +0000
committer P33M <2474547+P33M@users.noreply.github.com> Mon Mar 18 16:01:35 2024 +0000
tree 889d4da7f56f09a2bbf22ce2484657950b757787
parent af2540b045e585db715939f06943a4739a0f0eed

cdc_acm: turn on UART_TX LED when sending break signals

Software typically asserts line break for an extended period
(e.g. PuTTY will assert continuously until the next keypress), so
provide feedback via the LED.

Also declare variables used in both tinyusb callback and uart_thread context
as volatile.

src/cdc_uart.c

diff --git a/src/cdc_uart.c b/src/cdc_uart.c
index 5c79781..c6e4c67 100644
--- a/src/cdc_uart.c
+++ b/src/cdc_uart.c
@@ -32,8 +32,9 @@
 #include "probe_config.h"
 
 TaskHandle_t uart_taskhandle;
-TickType_t last_wake, interval = 100, break_expiry;
-bool timed_break;
+TickType_t last_wake, interval = 100;
+volatile TickType_t break_expiry;
+volatile bool timed_break;
 
 /* Max 1 FIFO worth of data */
 static uint8_t tx_buf[32];
@@ -43,7 +44,7 @@
 static uint debounce_ticks = 5;
 
 #ifdef PROBE_UART_TX_LED
-static uint tx_led_debounce;
+static volatile uint tx_led_debounce;
 #endif
 
 #ifdef PROBE_UART_RX_LED
@@ -145,6 +146,7 @@
         if (((int)break_expiry - (int)xTaskGetTickCount()) < 0) {
           timed_break = false;
           uart_set_break(PROBE_UART_INTERFACE, false);
+          tx_led_debounce = 0;
         } else {
           keep_alive = true;
         }
@@ -154,6 +156,7 @@
       uart_set_break(PROBE_UART_INTERFACE, false);
       timed_break = false;
       was_connected = 0;
+      tx_led_debounce = 0;
       cdc_tx_oe = 0;
     }
     return keep_alive;
@@ -275,11 +278,15 @@
     case 0xffff:
     uart_set_break(PROBE_UART_INTERFACE, true);
     timed_break = false;
+    gpio_put(PROBE_UART_TX_LED, 1);
+    tx_led_debounce = 1 << 30;
     break;
     default:
     uart_set_break(PROBE_UART_INTERFACE, true);
     timed_break = true;
+    gpio_put(PROBE_UART_TX_LED, 1);
     break_expiry = xTaskGetTickCount() + (wValue * (configTICK_RATE_HZ / 1000));
+    tx_led_debounce = 1 << 30;
     break;
   }
 }