targets: add support for Thumby

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

GNUmakefile

@@ -670,6 +670,8 @@ endif
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=ae-rp2040           examples/echo
 	@$(MD5SUM) test.hex
+	$(TINYGO) build -size short -o test.hex -target=thumby              examples/echo
+	@$(MD5SUM) test.hex
 	# test pwm
 	$(TINYGO) build -size short -o test.hex -target=itsybitsy-m0        examples/pwm
 	@$(MD5SUM) test.hex

src/machine/board_thumby.go

@@ -0,0 +1,94 @@
+//go:build thumby
+
+// This contains the pin mappings for the Thumby.
+//
+// https://thumby.us/
+package machine
+
+import (
+	"device/rp"
+	"runtime/interrupt"
+)
+
+const (
+	THUMBY_SCK_PIN = I2C1_SDA_PIN
+	THUMBY_SDA_PIN = I2C1_SCL_PIN
+
+	THUMBY_CS_PIN    = GPIO16
+	THUMBY_DC_PIN    = GPIO17
+	THUMBY_RESET_PIN = GPIO20
+
+	THUMBY_LINK_TX_PIN = UART0_TX_PIN
+	THUMBY_LINK_RX_PIN = UART0_RX_PIN
+	THUMBY_LINK_PU_PIN = GPIO2
+
+	THUMBY_BTN_LDPAD_PIN = GPIO3
+	THUMBY_BTN_RDPAD_PIN = GPIO5
+	THUMBY_BTN_UDPAD_PIN = GPIO4
+	THUMBY_BTN_DDPAD_PIN = GPIO6
+	THUMBY_BTN_B_PIN     = GPIO24
+	THUMBY_BTN_A_PIN     = GPIO27
+
+	THUMBY_AUDIO_PIN = GPIO28
+
+	THUMBY_SCREEN_RESET_PIN = GPIO20
+)
+
+// I2C pins
+const (
+	I2C0_SDA_PIN Pin = NoPin
+	I2C0_SCL_PIN Pin = NoPin
+
+	I2C1_SDA_PIN Pin = GPIO18
+	I2C1_SCL_PIN Pin = GPIO19
+)
+
+// SPI pins
+const (
+	SPI0_SCK_PIN = GPIO18
+	SPI0_SDO_PIN = GPIO19
+	SPI0_SDI_PIN = GPIO16
+
+	SPI1_SCK_PIN = NoPin
+	SPI1_SDO_PIN = NoPin
+	SPI1_SDI_PIN = NoPin
+)
+
+// Onboard crystal oscillator frequency, in MHz.
+const (
+	xoscFreq = 12 // MHz
+)
+
+// USB CDC identifiers
+const (
+	usb_STRING_PRODUCT      = "Thumby"
+	usb_STRING_MANUFACTURER = "TinyCircuits"
+)
+
+var (
+	usb_VID uint16 = 0x2E8A
+	usb_PID uint16 = 0x0005
+)
+
+// UART pins
+const (
+	UART0_TX_PIN = GPIO0
+	UART0_RX_PIN = GPIO1
+	UART_TX_PIN  = UART0_TX_PIN
+	UART_RX_PIN  = UART0_RX_PIN
+)
+
+// UART on the Thumby
+var (
+	UART0  = &_UART0
+	_UART0 = UART{
+		Buffer: NewRingBuffer(),
+		Bus:    rp.UART0,
+	}
+)
+
+var DefaultUART = UART0
+
+func init() {
+	UART0.Interrupt = interrupt.New(rp.IRQ_UART0_IRQ, _UART0.handleInterrupt)
+}

targets/thumby.json

@@ -0,0 +1,14 @@
+{
+    "inherits": [
+        "rp2040"
+    ],
+    "serial-port": ["2e8a:0005"],
+    "build-tags": ["thumby"],
+    "default-stack-size": 8192,
+    "ldflags": [
+        "--defsym=__flash_size=2048K"
+    ],
+    "extra-files": [
+        "targets/pico-boot-stage2.S"
+    ]
+}