From ede6b86a08ea3a749e1785c5263723c875b08359 Mon Sep 17 00:00:00 2001 From: Damien George Date: Fri, 12 Feb 2021 14:09:01 +1100 Subject: [PATCH] samd/mphalport: Fix USB CDC tx handling to work reliably. Signed-off-by: Damien George --- ports/samd/mphalport.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/ports/samd/mphalport.c b/ports/samd/mphalport.c index 67fc2cb0d6..357ec93a68 100644 --- a/ports/samd/mphalport.c +++ b/ports/samd/mphalport.c @@ -80,17 +80,16 @@ void mp_hal_stdout_tx_strn(const char *str, mp_uint_t len) { if (tud_cdc_connected()) { for (size_t i = 0; i < len;) { uint32_t n = len - i; - uint32_t n2 = tud_cdc_write(str + i, n); - if (n2 < n) { - while (!tud_cdc_write_flush()) { - __WFI(); - } + if (n > CFG_TUD_CDC_EP_BUFSIZE) { + n = CFG_TUD_CDC_EP_BUFSIZE; } + while (n > tud_cdc_write_available()) { + __WFI(); + } + uint32_t n2 = tud_cdc_write(str + i, n); + tud_cdc_write_flush(); i += n2; } - while (!tud_cdc_write_flush()) { - __WFI(); - } } while (len--) { while (!(USARTx->USART.INTFLAG.bit.DRE)) {