xiao-ble: initial support

targets/xiao-ble.json

@@ -0,0 +1,12 @@
+{
+	"inherits": ["nrf52840"],
+	"build-tags": ["xiao_ble", "softdevice", "s140v7"],
+	"serial": "uart",
+	"serial-port": ["acm:2886:8045", "acm:2886:0045"],
+	"flash-method": "msd",
+	"msd-volume-name": "XIAO-SENSE",
+	"msd-firmware-name": "firmware.uf2",
+	"binary-format": "uf2",
+	"uf2-family-id": "0xADA52840",
+	"linkerscript": "targets/xiao-ble.ld"
+}

targets/xiao-ble.ld

@@ -0,0 +1,18 @@
+
+/*
+  See also 
+  https://github.com/Seeed-Studio/ArduinoCore-mbed/blob/master/variants/SEEED_XIAO_NRF52840_SENSE/linker_script.ld
+*/
+MEMORY
+{
+    FLASH_TEXT (rx) : ORIGIN = 0x27000, LENGTH = 0xED000 - 0x27000
+    RAM (rwx) : ORIGIN = 0x20006000, LENGTH = 0x3A000
+}
+
+_stack_size = 4K + __softdevice_stack;
+
+/* This value is needed by the Nordic SoftDevice. */
+__app_ram_base = ORIGIN(RAM);
+__softdevice_stack = DEFINED(__softdevice_stack) ? __softdevice_stack : 0;
+
+INCLUDE "targets/arm.ld"