samples: peripherals: radio_test: Fix PPI endpoint clear and coded PHY RX

Fix endpoints_clear() to also clear NRF_TIMER_EVENT_COMPARE1 when
ENDPOINT_TIMER_RADIO_TX is set. Without this,
start_duty_cycle_modulated_tx did not work on retriggers
because radio_ppi_tx_reconfigure() attaches
COMPARE1 but endpoints_clear() only cleared COMPARE0.

Route coded PHY (BLE LR125/LR500) RX through DISABLED state using
END->DISABLE and DISABLED->RXEN shorts instead of END->START. This
ensures the receiver meets expected packet-loss behavior for Long
Range modes. Add a shell warning when start_rx is used with coded PHY.

Ported from sdk-nrf commits 7f07170da0 and 9145ec2458.

Signed-off-by: Ivan Iushkov <ivan.iushkov@nordicsemi.no>

Author: ivaniushkov

samples/peripherals/radio_test/src/radio_cmd.c

@@ -600,6 +600,19 @@ static int cmd_rx_start(const struct shell *shell, size_t argc, char **argv)
 	memset(&test_config, 0, sizeof(test_config));
 	test_config.type = RX;
 	test_config.mode = config.mode;
+
+	if (config.mode == NRF_RADIO_MODE_BLE_LR125KBIT ||
+	    config.mode == NRF_RADIO_MODE_BLE_LR500KBIT) {
+		shell_warn(
+			shell,
+			"Warning:\n Due to required post-processing in the receiver,"
+			" only every second packet sent by a device\n"
+			" running the start_tx_modulated_carrier command"
+			" with the configured data rate: %s can be received. Starting RX anyway.",
+			config.mode == NRF_RADIO_MODE_BLE_LR125KBIT ? "ble_lr125kbit"
+								    : "ble_lr500kbit");
+	}
+
 	test_config.params.rx.channel = config.channel_start;
 	test_config.params.rx.pattern = config.tx_pattern;
 

samples/peripherals/radio_test/src/radio_test.c

@@ -323,6 +323,8 @@ static void endpoints_clear(void)
 	if (atomic_test_and_clear_bit(&endpoint_state, ENDPOINT_TIMER_RADIO_TX)) {
 		nrfx_gppi_ep_clear(
 			nrf_timer_event_address_get(timer.p_reg, NRF_TIMER_EVENT_COMPARE0));
+		nrfx_gppi_ep_clear(
+			nrf_timer_event_address_get(timer.p_reg, NRF_TIMER_EVENT_COMPARE1));
 		nrfx_gppi_ep_clear(nrf_radio_task_address_get(NRF_RADIO, NRF_RADIO_TASK_TXEN));
 	}
 }
@@ -695,9 +697,14 @@ static void radio_rx(uint8_t mode, uint8_t channel, enum transmit_pattern patter
 
 	radio_mode_set(NRF_RADIO, mode);
 
-	nrf_radio_shorts_enable(NRF_RADIO,
-				NRF_RADIO_SHORT_READY_START_MASK |
-				NRF_RADIO_SHORT_END_START_MASK);
+	if ((mode == NRF_RADIO_MODE_BLE_LR125KBIT) || (mode == NRF_RADIO_MODE_BLE_LR500KBIT)) {
+		nrf_radio_shorts_enable(NRF_RADIO, NRF_RADIO_SHORT_READY_START_MASK |
+						   RADIO_TEST_SHORT_END_DISABLE_MASK |
+						   NRF_RADIO_SHORT_DISABLED_RXEN_MASK);
+	} else {
+		nrf_radio_shorts_enable(NRF_RADIO, NRF_RADIO_SHORT_READY_START_MASK |
+						   NRF_RADIO_SHORT_END_START_MASK);
+	}
 	nrf_radio_packetptr_set(NRF_RADIO, rx_packet);
 
 	radio_config(mode, pattern);