targets: WIP on Arduino Uno R4

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

targets/arduino-unor4.json

@@ -0,0 +1,7 @@
+{
+	"inherits": ["ra4m1"],
+	"build-tags": ["arduino_unor4"],
+	"flash-command": "bossac -i -e -w -v -R -U --port={port} --offset=0x4000 {bin}",
+    "serial-port": ["2341:8057", "2341:0057"],
+    "flash-1200-bps-reset": "true"
+}

targets/ra4m1.json

@@ -1,10 +1,8 @@
 {
 	"inherits": ["cortex-m4"],
-	"build-tags": ["ra4m1", "renesas"],
+	"build-tags": ["ra4m1", "r7fa4m1ab", "renesas"],
 	"linkerscript": "targets/ra4m1.ld",
 	"extra-files": [
-		"src/device/renesas/r7fa4m2ad.s"
-	],
-	"openocd-transport": "swd",
-	"openocd-target": "atsame5x"
+		"src/device/renesas/r7fa4m1ab.s"
+	]
 }

targets/ra4m1.ld

@@ -2,7 +2,7 @@
 MEMORY
 {
     FLASH_TEXT (rw) : ORIGIN = 0x00000000+0x4000, LENGTH = 0x00080000-0x4000  /* First 16KB used by bootloader */
-    RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 0x00030000
+    RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 0x00040000
 }
 
 _stack_size = 4K;