From 212f89e61a96f9755590bc6f7c807808af5c057e Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Sun, 13 Apr 2014 16:39:04 +0100
Subject: [PATCH] stmhal: Improve USB CDC write function (increase timeout).
---
stmhal/usbd_cdc_interface.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff --git a/stmhal/usbd_cdc_interface.c b/stmhal/usbd_cdc_interface.c
index 693f51b7c..81f541df4 100644
--- a/stmhal/usbd_cdc_interface.c
+++ b/stmhal/usbd_cdc_interface.c
@@ -362,12 +362,10 @@ void USBD_CDC_SetInterrupt(int chr, void *data) {
void USBD_CDC_Tx(const char *str, uint32_t len) {
for (int i = 0; i < len; i++) {
- uint timeout = 200;
- while (((UserTxBufPtrIn + 1) & (APP_TX_DATA_SIZE - 1)) == UserTxBufPtrOut) {
- if (timeout-- == 0) {
- break;
- }
- HAL_Delay(1);
+ // if the buffer is full, wait until it gets drained, with a timeout of 1000ms (wraparound of tick is taken care of by 2's complement arithmetic)
+ uint32_t start = HAL_GetTick();
+ while (((UserTxBufPtrIn + 1) & (APP_TX_DATA_SIZE - 1)) == UserTxBufPtrOut && HAL_GetTick() - start <= 1000) {
+ __WFI(); // enter sleep mode, waiting for interrupt
}
UserTxBuffer[UserTxBufPtrIn] = str[i];
UserTxBufPtrIn = (UserTxBufPtrIn + 1) & (APP_TX_DATA_SIZE - 1);
--
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