From 83e0dd9ba7642e98e52339671de0b6c62902e9a8 Mon Sep 17 00:00:00 2001 From: Eric Wild Date: Thu, 12 Nov 2020 01:30:38 +0100 Subject: sercom: make waiting for the uart safe... In error cases the uart might already be disabled, so waiting for the dre bit does not work. Change-Id: I269cf8ece48df24c9f1fcb262ef4ddd06cbe3d62 --- sysmoOCTSIM/cuart_driver_asf4_usart_async.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/sysmoOCTSIM/cuart_driver_asf4_usart_async.c b/sysmoOCTSIM/cuart_driver_asf4_usart_async.c index e6d180c..64ec9f2 100644 --- a/sysmoOCTSIM/cuart_driver_asf4_usart_async.c +++ b/sysmoOCTSIM/cuart_driver_asf4_usart_async.c @@ -5,6 +5,7 @@ #include #include +#include #include #include #include "driver_init.h" @@ -228,8 +229,13 @@ static bool slot_set_baudrate(struct card_uart *cuart, uint32_t baudrate) cuart->u.asf4.extrawait_after_rx = 1./baudrate * 1000 * 1000; printf("(%u) switching SERCOM clock to GCLK%u (freq = %lu kHz) and baud rate to %lu bps (baud = %u)\r\n", slotnr, (best + 1) * 2, (uint32_t)(round(sercom_glck_freqs[best] / 1000)), baudrate, bauds[best]); - while (!usart_async_is_tx_empty(slot)); // wait for transmission to complete (WARNING no timeout) - usart_async_disable(slot); // disable SERCOM peripheral + + /* only wait if the uart is enabled.... */ + if (hri_sercomusart_get_CTRLA_reg(slot->device.hw, SERCOM_USART_CTRLA_ENABLE)) { + while (!usart_async_is_tx_empty(slot)); // wait for transmission to complete (WARNING no timeout) + usart_async_disable(slot); // disable SERCOM peripheral + } + hri_gclk_clear_PCHCTRL_reg(GCLK, SIM_peripheral_GCLK_ID[slotnr], (1 << GCLK_PCHCTRL_CHEN_Pos)); // disable clock for this peripheral while (hri_gclk_get_PCHCTRL_reg(GCLK, SIM_peripheral_GCLK_ID[slotnr], (1 << GCLK_PCHCTRL_CHEN_Pos))); // wait until clock is really disabled // it does not seem we need to completely disable the peripheral using hri_mclk_clear_APBDMASK_SERCOMn_bit -- cgit v1.2.3