microbit: A sample program using yotta

This commit adds the bbc-microbit-armcc target, and
also includes the microbit dal, showing how the microbit
can be compiled using yotta.

.gitignore

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+build
+yotta_modules
+yotta_targets/*
+
+!.gitignore
+
+!yotta_targets/bbc-microbit-armcc

.yotta.json

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+{
+  "build": {
+    "target": "bbc-microbit-armcc,*"
+  }
+}

module.json

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+{
+  "name": "microbit",
+  "version": "0.0.1",
+  "description": "The micro:bit runtime, building with yotta",
+  "licenses": [
+    {
+      "url": "https://spdx.org/licenses/Apache-2.0",
+      "type": "Apache-2.0"
+    }
+  ],
+  "dependencies": {
+      "mbed-classic": "~0.0.4",
+      "ble": "jamesadevine/BLE_API",
+      "ble-nrf51822": "jamesadevine/nrf51822",
+	    "microbit-dal":"jamesadevine/microbit-dal"
+  },
+  "targetDependencies": {},
+  "bin": "./source"
+}
+

source/main.cpp

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+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2015 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.
+ */
+
+#include "MicroBit.h"
+
+DigitalOut led1(LED1);
+
+void periodicCallback(void)
+{
+     /* Do blinky on LED1 while we're waiting for BLE events */
+}
+
+void app_main()
+{
+    led1 = 1;
+	
+    // infinite loop
+    while (1)
+	{
+		uBit.display.scrollString("ABC123");
+		uBit.sleep(1000);
+	}
+}

yotta_targets/bbc-microbit-armcc/.gitignore

@@ -0,0 +1,6 @@
+build
+yotta_targets
+yotta_modules
+upload.tar.gz
+.DS_Store
+.yotta.json

yotta_targets/bbc-microbit-armcc/CMake/toolchain.cmake

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+# Copyright (C) 2014-2015 ARM Limited. All rights reserved.
+
+if(TARGET_NORDIC_NRF51822_16K_ARMCC_TOOLCHAIN_INCLUDED)
+    return()
+endif()
+set(TARGET_NORDIC_NRF51822_16K_ARMCC_TOOLCHAIN_INCLUDED 1)
+
+# legacy definitions for building mbed 2.0 modules with a retrofitted build
+# system:
+set(MBED_LEGACY_TARGET_DEFINITIONS "NORDIC" "NRF51_MICROBIT" "MCU_NRF51822" "MCU_NRF51_16K" "MCU_NORDIC_16K" "MCU_NRF51_16K_S110")
+# provide compatibility definitions for compiling with this target: these are
+# definitions that legacy code assumes will be defined.
+add_definitions("-DNRF51 -DTARGET_NORDIC -DTARGET_M0 -D__MBED__=1 -DMCU_NORDIC_16K -DTARGET_NRF51_MICROBIT -DTARGET_MCU_NORDIC_16K -DTARGET_MCU_NRF51_16K_S110  -DTARGET_NRF_LFCLK_RC -DTARGET_MCU_NORDIC_16K -D__CORTEX_M0 -DARM_MATH_CM0")
+
+# append non-generic flags, and set NRF51822-specific link script
+set(_CPU_COMPILATION_OPTIONS "--CPU=Cortex-M0 -D__thumb2__")
+
+set(CMAKE_C_FLAGS_INIT             "${CMAKE_C_FLAGS_INIT} ${_CPU_COMPILATION_OPTIONS}")
+set(CMAKE_ASM_FLAGS_INIT           "${CMAKE_ASM_FLAGS_INIT} ${_CPU_COMPILATION_OPTIONS}")
+set(CMAKE_CXX_FLAGS_INIT           "${CMAKE_CXX_FLAGS_INIT} ${_CPU_COMPILATION_OPTIONS}")
+#set(CMAKE_MODULE_LINKER_FLAGS_INIT "${CMAKE_MODULE_LINKER_FLAGS_INIT}")
+set(CMAKE_EXE_LINKER_FLAGS_INIT    "${CMAKE_EXE_LINKER_FLAGS_INIT} --info=totals --list=.link_totals.txt --scatter ${CMAKE_CURRENT_LIST_DIR}/../ld/nRF51822.sct")
+
+# used by the apply_target_rules function below:
+set(NRF51822_SOFTDEVICE_HEX_FILE "${CMAKE_CURRENT_LIST_DIR}/../softdevice/s110_nrf51822_8.0.0_softdevice.hex")
+
+# define a function for yotta to apply target-specific rules to build products,
+# in our case we need to convert the built elf file to .hex, and add the
+# pre-built softdevice:
+function(yotta_apply_target_rules target_type target_name)
+    if(${target_type} STREQUAL "EXECUTABLE")
+        # !!! FIXME: is there an armcc toolchain command that can be used to
+        # do this? (instead of needing binutils' objcopy)
+        add_custom_command(TARGET ${target_name}
+            POST_BUILD
+            COMMAND arm-none-eabi-size ${target_name}
+            # fromelf to hex
+            COMMAND fromelf --i32combined --output=${target_name}.hex ${target_name}
+            # and append the softdevice hex file
+            COMMAND srec_cat ${NRF51822_SOFTDEVICE_HEX_FILE} -intel ${target_name}.hex -intel -o ${target_name}-combined.hex -intel --line-length=44
+            COMMAND srec_info ${target_name}-combined.hex -intel
+            COMMENT "hexifying and adding softdevice to ${target_name}"
+            VERBATIM
+        )
+    endif()
+endfunction()

yotta_targets/bbc-microbit-armcc/ld/nRF51822.sct

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+;WITHOUT SOFTDEVICE:
+;LR_IROM1 0x00000000 0x00040000  {
+;  ER_IROM1 0x00000000 0x00040000  {
+;   *.o (RESET, +First)
+;   *(InRoot$$Sections)
+;   .ANY (+RO)
+;  }
+;  RW_IRAM1 0x20000000 0x00004000  {
+;   .ANY (+RW +ZI)
+;  }
+;}
+;
+;WITH SOFTDEVICE:
+
+LR_IROM1 0x18000 0x0028000  {
+  ER_IROM1 0x18000 0x0028000  {
+   *.o (RESET, +First)
+   *(InRoot$$Sections)
+   .ANY (+RO)
+  }
+  RW_IRAM1 0x20002000 0x00002000  {
+   .ANY (+RW +ZI)
+  }
+}

yotta_targets/bbc-microbit-armcc/readme.md

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+## yotta Target Description using ARMCC to compile for Nordic nRF51822 16KB device.
+

yotta_targets/bbc-microbit-armcc/target.json

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+{
+  "name": "bbc-microbit-armcc",
+  "version": "0.0.1",
+  "description": "Official mbed build target for the microbit, using the armcc toolchain.",
+  "licenses": [
+    {
+      "url": "https://spdx.org/licenses/Apache-2.0",
+      "type": "Apache-2.0"
+    }
+  ],
+  "inherits": {
+    "mbed-armcc": "*"
+  },
+  "keywords": [
+    "mbed-target:nrf51822",
+    "mbed-official",
+    "nrf51822",
+    "nordic",
+    "armcc",
+	"microbit"
+  ],
+  "config": {},
+  "similarTo": [
+    "nrf51822",
+    "nrf",
+    "nordic",
+    "cortex-m0",
+    "armv6-m",
+    "mbed-classic"
+  ],
+  "toolchain": "CMake/toolchain.cmake",
+  "scripts": {
+    "debug": [
+      "valinor",
+      "--target",
+      "NRF51_MICROBIT",
+      "$program"
+    ],
+    "test": [
+      "mbed_test_wrapper",
+      "--target",
+      "NRF51_MICROBIT",
+      "$program"
+    ]
+  }
+}