itm_api.c implementation for Nordic NRF52 series

SWO frequency: 4000 kHz

targets/TARGET_NORDIC/TARGET_NRF5/itm_api.c

@@ -0,0 +1,44 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#if defined(DEVICE_ITM)
+
+#include "hal/itm_api.h"
+
+#include "nrf.h"
+#include "nrf5x_lf_clk_helper.h"
+
+/* SWO frequency: 4000 kHz */
+void itm_init(void)
+{
+    /* Enable SWO trace functionality */
+    CoreDebug->DEMCR |= CoreDebug_DEMCR_TRCENA_Msk;
+    NRF_CLOCK->TRACECONFIG |= CLOCK_TRACECONFIG_TRACEMUX_Serial << CLOCK_TRACECONFIG_TRACEMUX_Pos;
+
+    /* set SWO clock speed to 4 MHz */
+    NRF_CLOCK->TRACECONFIG = (NRF_CLOCK->TRACECONFIG & ~CLOCK_TRACECONFIG_TRACEPORTSPEED_Msk) | 
+                             (CLOCK_TRACECONFIG_TRACEPORTSPEED_4MHz << CLOCK_TRACECONFIG_TRACEPORTSPEED_Pos);
+
+    /* set SWO pin */
+    NRF_P0->PIN_CNF[18] = (GPIO_PIN_CNF_DRIVE_H0H1 << GPIO_PIN_CNF_DRIVE_Pos) | 
+                          (GPIO_PIN_CNF_INPUT_Connect << GPIO_PIN_CNF_INPUT_Pos) | 
+                          (GPIO_PIN_CNF_DIR_Output << GPIO_PIN_CNF_DIR_Pos);
+
+    /* set prescaler */
+    TPI->ACPR = 0;
+}
+
+#endif

targets/targets.json

@@ -3443,7 +3443,7 @@
         "inherits": ["Target"],
         "core": "Cortex-M4F",
         "macros": ["NRF52", "TARGET_NRF52832", "BLE_STACK_SUPPORT_REQD", "SOFTDEVICE_PRESENT", "S132", "CMSIS_VECTAB_VIRTUAL", "CMSIS_VECTAB_VIRTUAL_HEADER_FILE=\"cmsis_nvic.h\"", "MBED_TICKLESS"],
-        "device_has": ["STCLK_OFF_DURING_SLEEP"],
+        "device_has": ["STCLK_OFF_DURING_SLEEP", "ITM"],
         "extra_labels": ["NORDIC", "MCU_NRF52", "MCU_NRF52832", "NRF5", "SDK11", "NRF52_COMMON"],
         "OUTPUT_EXT": "hex",
         "is_disk_virtual": true,
@@ -3546,7 +3546,7 @@
         "inherits": ["Target"],
         "core": "Cortex-M4F",
         "macros": ["TARGET_NRF52840", "BLE_STACK_SUPPORT_REQD", "SOFTDEVICE_PRESENT", "S140", "NRF_SD_BLE_API_VERSION=5", "NRF52840_XXAA", "NRF_DFU_SETTINGS_VERSION=1", "NRF_SD_BLE_API_VERSION=5", "CMSIS_VECTAB_VIRTUAL", "CMSIS_VECTAB_VIRTUAL_HEADER_FILE=\"cmsis_nvic.h\"", "MBED_TICKLESS"],
-        "device_has": ["STCLK_OFF_DURING_SLEEP"],
+        "device_has": ["STCLK_OFF_DURING_SLEEP", "ITM"],
         "extra_labels": ["NORDIC", "MCU_NRF52840", "NRF5", "SDK13", "NRF52_COMMON"],
         "OUTPUT_EXT": "hex",
         "is_disk_virtual": true,