drivers: serial: nrfx_uarte: Fix spurious RXTO event (e235e7b3) · Commits · Wenxi XU / zephyr

Fast instance in nrf54h (uart120) can generate a spurious RXTO event some time after RXTO event that indicates that RX path is disabled. The time when event is generated depends on baudrate and when slower baudrates are used peripheral is disabled on time to not notice it in the test but with higher baudates issue become visible. In order to avoid spurious interrupt, RXTO interrupt is disabled during RXTO event handling and enabled when RX is enabled. This workaround is applied only for fast instance to avoid unnecessary register accesses for slower instances. Signed-off-by:

Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>

drivers/serial/uart_nrfx_uarte.c

+14 −0

Changes for drivers/serial/uart_nrfx_uarte.c: 14 added lines, 0 removed lines.
Original line number	Diff line number	Diff line
		@@ -1165,6 +1165,14 @@ static int uarte_nrfx_rx_enable(const struct device dev, uint8_t buf,

		nrf_uarte_rx_buffer_set(uarte, buf, len);

		if (IS_ENABLED(UARTE_ANY_FAST_PD) && (cfg->flags & UARTE_CFG_FLAG_CACHEABLE)) {
		/* Spurious RXTO event was seen on fast instance (UARTE120) thus
		* RXTO interrupt is kept enabled only when RX is active.
		*/
		nrf_uarte_event_clear(uarte, NRF_UARTE_EVENT_RXTO);
		nrf_uarte_int_enable(uarte, NRF_UARTE_INT_RXTO_MASK);
		}

		nrf_uarte_event_clear(uarte, NRF_UARTE_EVENT_ENDRX);
		nrf_uarte_event_clear(uarte, NRF_UARTE_EVENT_RXSTARTED);

		@@ -1637,6 +1645,12 @@ static void rxto_isr(const struct device *dev)

		#ifdef CONFIG_UART_NRFX_UARTE_ENHANCED_RX
		NRF_UARTE_Type *uarte = get_uarte_instance(dev);
		if (IS_ENABLED(UARTE_ANY_FAST_PD) && (config->flags & UARTE_CFG_FLAG_CACHEABLE)) {
		/* Spurious RXTO event was seen on fast instance (UARTE120) thus
		* RXTO interrupt is kept enabled only when RX is active.
		*/
		nrf_uarte_int_disable(uarte, NRF_UARTE_INT_RXTO_MASK);
		}
		#ifdef UARTE_HAS_FRAME_TIMEOUT
		nrf_uarte_shorts_disable(uarte, NRF_UARTE_SHORT_FRAME_TIMEOUT_STOPRX);
		#endif

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