Support ITM tracing for Ambiq Apollo3 targets

targets/TARGET_Ambiq_Micro/TARGET_Apollo3/CMakeLists.txt

@@ -51,6 +51,7 @@ target_sources(mbed-apollo3
         device/sleep.c
         device/spi_api.c
         device/us_ticker.c
+        device/itm_api.c
 
         sdk/CMSIS/AmbiqMicro/Source/system_apollo3.c
 

targets/TARGET_Ambiq_Micro/TARGET_Apollo3/device/itm_api.c

@@ -0,0 +1,48 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 ARM Limited
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * 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 DEVICE_ITM
+
+#include "hal/itm_api.h"
+#include "cmsis.h"
+#include "am_bsp.h"
+
+#include <stdbool.h>
+
+/* SWO frequency: 1000 kHz */
+
+#ifndef AM_BSP_GPIO_ITM_SWO
+#define AM_GPIO_ITM_SWO             	22
+
+const am_hal_gpio_pincfg_t g_AM_GPIO_ITM_SWO =
+{
+    .uFuncSel            = AM_HAL_PIN_22_SWO,
+    .eDriveStrength      = AM_HAL_GPIO_PIN_DRIVESTRENGTH_2MA
+};
+#endif 
+
+
+void itm_init(void)
+{
+    #ifdef AM_BSP_GPIO_ITM_SWO
+    am_bsp_itm_printf_enable();
+    #else
+    am_bsp_itm_printf_enable(AM_GPIO_ITM_SWO,g_AM_GPIO_ITM_SWO);
+    #endif
+}
+
+#endif

targets/targets.json

@@ -9061,7 +9061,8 @@
             "FLASH",
             "SPI",
             "I2C",
-            "SLEEP"
+            "SLEEP",
+            "ITM"
         ],
         "components": [
             "FLASHIAP"