pca10056: support this nrf52840-based board

Signed-off-by: Ron Evans <ron@hybridgroup.com>

.travis.yml

@@ -27,3 +27,5 @@ script:
   - tinygo build -o blinky1.nrf51d.elf -target=pca10031     examples/blinky1
   - tinygo build -o blinky1.stm32.elf  -target=bluepill     examples/blinky1
   - tinygo build -o blinky1.avr.o      -target=arduino      examples/blinky1 # TODO: avr-as/avr-gcc doesn't work
+  - tinygo build -o blinky1.pca10056.elf    -target=pca10056     examples/blinky1
+  - tinygo build -o blinky2.pca10056.elf    -target=pca10056     examples/blinky2

docs/targets.rst

@@ -38,6 +38,8 @@ technology (LLVM) as the proprietary ARM compiler for code generation.
     <https://www.nordicsemi.com/eng/Products/Bluetooth-low-energy/nRF52832>`_)
   * `nRF52840-MDK <https://wiki.makerdiary.com/nrf52840-mdk/>`_ (`nRF52840
     <https://www.nordicsemi.com/eng/Products/nRF52840>`_)
+  * `Nordic PCA10056 <https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF52840-DK>`_ (`nRF52840
+    <https://www.nordicsemi.com/eng/Products/nRF52840>`_)
   * `QEMU <https://wiki.qemu.org/Documentation/Platforms/ARM>`_ (`LM3S6965
     <http://www.ti.com/product/LM3S6965>`_) |br|
     This target is supported only for testing purposes. It has not been tested

src/machine/board_pca10056.go

@@ -0,0 +1,35 @@
+// +build pca10056
+
+package machine
+
+const HasLowFrequencyCrystal = true
+
+// LEDs on the pca10056
+const (
+	LED  = LED1
+	LED1 = 13
+	LED2 = 14
+	LED3 = 15
+	LED4 = 16
+)
+
+// Buttons on the pca10056
+const (
+	BUTTON  = BUTTON1
+	BUTTON1 = 11
+	BUTTON2 = 12
+	BUTTON3 = 24
+	BUTTON4 = 25
+)
+
+// UART pins
+const (
+	UART_TX_PIN = 6
+	UART_RX_PIN = 8
+)
+
+// I2C pins
+const (
+	SDA_PIN = 26
+	SCL_PIN = 27
+)

targets/pca10056.json

@@ -0,0 +1,7 @@
+{
+	"inherits": ["nrf52840"],
+	"build-tags": ["pca10056"],
+	"flash": "nrfjprog -f nrf52 --sectorerase --program {hex} --reset",
+	"ocd-daemon": ["openocd", "-f", "interface/cmsis-dap.cfg", "-f", "target/nrf51.cfg"],
+	"gdb-initial-cmds": ["target remote :3333", "monitor halt", "load", "monitor reset", "c"]
+}