samples: BT DTM: Replace timer wait with k_sleep in 2-wire UART

doki-nordic · rlubos · commit 31c396e515b0 · 2025-09-10T09:31:41.000+02:00
The 2-wire UART protocol in DTM uses a timer to wait during
polling. The k_sleep has no disadvantages over it and it
does not take additional resources. k_sleep will be more
optimal.

Signed-off-by: Dominik Kilian &lt;Dominik.Kilian@nordicsemi.no&gt;
diff --git a/doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst b/doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst
@@ -292,6 +292,11 @@ Bluetooth samples
    * :ref:`peripheral_status`
    * :ref:`peripheral_uart`
 
+* :ref:`direct_test_mode` sample:
+
+  * Updated by simplifying the 2-wire UART polling.
+    This is done by replacing the hardware timer with the ``k_sleep()`` function.
+
 Bluetooth Mesh samples
 ----------------------
 
diff --git a/samples/bluetooth/direct_test_mode/CMakeLists.txt b/samples/bluetooth/direct_test_mode/CMakeLists.txt
@@ -12,7 +12,6 @@ target_include_directories(app PRIVATE ./src)
 
 target_sources_ifndef(CONFIG_DTM_TRANSPORT_HCI app PRIVATE
   src/transport/dtm_uart_twowire.c
-  src/transport/dtm_uart_wait.c
 )
 
 target_sources_ifdef(CONFIG_DTM_TRANSPORT_HCI app PRIVATE src/transport/dtm_hci.c)
diff --git a/samples/bluetooth/direct_test_mode/boards/nrf54h20dk_nrf54h20_cpurad.conf b/samples/bluetooth/direct_test_mode/boards/nrf54h20dk_nrf54h20_cpurad.conf
@@ -6,12 +6,10 @@
 
 # Disable the unsupported driver
 CONFIG_NRFX_TIMER0=n
-CONFIG_NRFX_TIMER1=n
 CONFIG_NRFX_TIMER2=n
 
 # Use necessary peripherals
 CONFIG_NRFX_TIMER020=y
-CONFIG_NRFX_TIMER021=y
 
 CONFIG_MAIN_STACK_SIZE=2048
 CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
diff --git a/samples/bluetooth/direct_test_mode/boards/nrf54l15dk_nrf54l05_cpuapp.conf b/samples/bluetooth/direct_test_mode/boards/nrf54l15dk_nrf54l05_cpuapp.conf
@@ -6,9 +6,7 @@
 
 # Disable the unsupported driver
 CONFIG_NRFX_TIMER0=n
-CONFIG_NRFX_TIMER1=n
 CONFIG_NRFX_TIMER2=n
 
 # Use necessary peripherals
-CONFIG_NRFX_TIMER20=y
 CONFIG_NRFX_TIMER10=y
diff --git a/samples/bluetooth/direct_test_mode/boards/nrf54l15dk_nrf54l10_cpuapp.conf b/samples/bluetooth/direct_test_mode/boards/nrf54l15dk_nrf54l10_cpuapp.conf
@@ -6,9 +6,7 @@
 
 # Disable the unsupported driver
 CONFIG_NRFX_TIMER0=n
-CONFIG_NRFX_TIMER1=n
 CONFIG_NRFX_TIMER2=n
 
 # Use necessary peripherals
-CONFIG_NRFX_TIMER20=y
 CONFIG_NRFX_TIMER10=y
diff --git a/samples/bluetooth/direct_test_mode/boards/nrf54l15dk_nrf54l15_cpuapp.conf b/samples/bluetooth/direct_test_mode/boards/nrf54l15dk_nrf54l15_cpuapp.conf
@@ -6,9 +6,7 @@
 
 # Disable the unsupported driver
 CONFIG_NRFX_TIMER0=n
-CONFIG_NRFX_TIMER1=n
 CONFIG_NRFX_TIMER2=n
 
 # Use necessary peripherals
-CONFIG_NRFX_TIMER20=y
 CONFIG_NRFX_TIMER10=y
diff --git a/samples/bluetooth/direct_test_mode/boards/nrf54lm20dk_nrf54lm20a_cpuapp.conf b/samples/bluetooth/direct_test_mode/boards/nrf54lm20dk_nrf54lm20a_cpuapp.conf
@@ -6,9 +6,7 @@
 
 # Disable the unsupported driver
 CONFIG_NRFX_TIMER0=n
-CONFIG_NRFX_TIMER1=n
 CONFIG_NRFX_TIMER2=n
 
 # Use necessary peripherals
-CONFIG_NRFX_TIMER20=y
 CONFIG_NRFX_TIMER10=y
diff --git a/samples/bluetooth/direct_test_mode/boards/nrf54lv10dk_nrf54lv10a_cpuapp.conf b/samples/bluetooth/direct_test_mode/boards/nrf54lv10dk_nrf54lv10a_cpuapp.conf
@@ -6,9 +6,7 @@
 
 # Disable the unsupported driver
 CONFIG_NRFX_TIMER0=n
-CONFIG_NRFX_TIMER1=n
 CONFIG_NRFX_TIMER2=n
 
 # Use necessary peripherals
-CONFIG_NRFX_TIMER20=y
 CONFIG_NRFX_TIMER10=y
diff --git a/samples/bluetooth/direct_test_mode/prj.conf b/samples/bluetooth/direct_test_mode/prj.conf
@@ -21,7 +21,6 @@ CONFIG_LOG_BACKEND_RTT=y
 
 # Use necessary peripherals
 CONFIG_NRFX_TIMER0=y
-CONFIG_NRFX_TIMER1=y
 CONFIG_NRFX_TIMER2=y
 CONFIG_NRFX_GPPI=y
 CONFIG_CLOCK_CONTROL=y
diff --git a/samples/bluetooth/direct_test_mode/prj_hci.conf b/samples/bluetooth/direct_test_mode/prj_hci.conf
@@ -21,7 +21,6 @@ CONFIG_LOG_BACKEND_RTT=y
 
 # Use necessary peripherals
 CONFIG_NRFX_TIMER0=y
-CONFIG_NRFX_TIMER1=y
 CONFIG_NRFX_TIMER2=y
 CONFIG_NRFX_GPPI=y
 CONFIG_CLOCK_CONTROL=y
diff --git a/samples/bluetooth/direct_test_mode/prj_usb.conf b/samples/bluetooth/direct_test_mode/prj_usb.conf
@@ -21,7 +21,6 @@ CONFIG_LOG_BACKEND_RTT=y
 
 # Use necessary peripherals
 CONFIG_NRFX_TIMER0=y
-CONFIG_NRFX_TIMER1=y
 CONFIG_NRFX_TIMER2=y
 CONFIG_NRFX_GPPI=y
 CONFIG_CLOCK_CONTROL=y
diff --git a/samples/bluetooth/direct_test_mode/src/transport/dtm_uart_twowire.c b/samples/bluetooth/direct_test_mode/src/transport/dtm_uart_twowire.c
@@ -10,7 +10,6 @@
 #include <zephyr/kernel.h>
 #include <dtm.h>
 
-#include "dtm_uart_wait.h"
 #include "dtm_transport.h"
 
 LOG_MODULE_REGISTER(dtm_tw_tr, CONFIG_DTM_TRANSPORT_LOG_LEVEL);
@@ -70,6 +69,22 @@ LOG_MODULE_REGISTER(dtm_tw_tr, CONFIG_DTM_TRANSPORT_LOG_LEVEL);
 /* The DTM maximum wait time in milliseconds for the UART command second byte. */
 #define DTM_UART_SECOND_BYTE_MAX_DELAY 5
 
+#define DTM_UART DT_CHOSEN(ncs_dtm_uart)
+
+#if DT_NODE_HAS_PROP(DTM_UART, current_speed)
+/* UART Baudrate used to communicate with the DTM library. */
+#define DTM_UART_BAUDRATE DT_PROP(DTM_UART, current_speed)
+
+/* The UART poll cycle in micro seconds.
+ * A baud rate of e.g. 19200 bits / second, and 8 data bits, 1 start/stop bit,
+ * no flow control, give the time to transmit a byte:
+ * 10 bits * 1/19200 = approx: 520 us.
+ */
+#define DTM_UART_POLL_CYCLE_US ((uint32_t) (10 * 1e6 / DTM_UART_BAUDRATE))
+#else
+#error "DTM UART node not found"
+#endif /* DT_NODE_HAS_PROP(DTM_UART, currrent_speed) */
+
 static const struct device *dtm_uart = DEVICE_DT_GET(DTM_UART);
 
 /* DTM command codes */
@@ -750,11 +765,6 @@ int dtm_tr_init(void)
 		return err;
 	}
 
-	err = dtm_uart_wait_init();
-	if (err) {
-		return err;
-	}
-
 	return 0;
 }
 
@@ -768,7 +778,7 @@ union dtm_tr_packet dtm_tr_get(void)
 	int err;
 
 	for (;;) {
-		dtm_uart_wait();
+		k_sleep(K_USEC(DTM_UART_POLL_CYCLE_US));
 
 		err = uart_poll_in(dtm_uart, &rx_byte);
 		if (err) {
diff --git a/samples/bluetooth/direct_test_mode/src/transport/dtm_uart_wait.c b/samples/bluetooth/direct_test_mode/src/transport/dtm_uart_wait.c
diff --git a/samples/bluetooth/direct_test_mode/src/transport/dtm_uart_wait.h b/samples/bluetooth/direct_test_mode/src/transport/dtm_uart_wait.h

Original file line number	Diff line number	Diff line change
`@@ -12,7 +12,6 @@ target_include_directories(app PRIVATE ./src)`
`12`	`12`
`13`	`13`	`target_sources_ifndef(CONFIG_DTM_TRANSPORT_HCI app PRIVATE`
`14`	`14`	`src/transport/dtm_uart_twowire.c`
`15`		`- src/transport/dtm_uart_wait.c`
`16`	`15`	`)`
`17`	`16`
`18`	`17`	`target_sources_ifdef(CONFIG_DTM_TRANSPORT_HCI app PRIVATE src/transport/dtm_hci.c)`