From 394884617ebb957592024a240feb752ffef19260 Mon Sep 17 00:00:00 2001
From: Dave Cheney <dave@cheney.net>
Date: Sat, 12 Sep 2026 13:27:01 +1000
Subject: [PATCH] Add support for Waveshare RP2040-PiZero board

---
 make/smoketest.mk                            |   2 +
 src/machine/board_waveshare-rp2040-pizero.go | 103 +++++++++++++++++++
 targets/waveshare-rp2040-pizero.json         |  14 +++
 3 files changed, 119 insertions(+)
 create mode 100644 src/machine/board_waveshare-rp2040-pizero.go
 create mode 100644 targets/waveshare-rp2040-pizero.json

diff --git a/make/smoketest.mk b/make/smoketest.mk
index ac42496be..73d2353d0 100644
--- a/make/smoketest.mk
+++ b/make/smoketest.mk
@@ -295,6 +295,8 @@ smoketest-rp2xxx: | build/smoke
 	@$(MD5SUM) $(SMOKE_OUT).hex
 	$(TINYGO) build -size short -o $(SMOKE_OUT).hex -target=waveshare-rp2040-zero examples/echo
 	@$(MD5SUM) $(SMOKE_OUT).hex
+	$(TINYGO) build -size short -o $(SMOKE_OUT).hex -target=waveshare-rp2040-pizero examples/echo
+	@$(MD5SUM) $(SMOKE_OUT).hex
 	$(TINYGO) build -size short -o $(SMOKE_OUT).hex -target=challenger-rp2040    examples/blinky1
 	@$(MD5SUM) $(SMOKE_OUT).hex
 	$(TINYGO) build -size short -o $(SMOKE_OUT).hex -target=trinkey-qt2040      examples/temp
diff --git a/src/machine/board_waveshare-rp2040-pizero.go b/src/machine/board_waveshare-rp2040-pizero.go
new file mode 100644
index 000000000..653a9e87a
--- /dev/null
+++ b/src/machine/board_waveshare-rp2040-pizero.go
@@ -0,0 +1,103 @@
+//go:build waveshare_rp2040_pizero
+
+// This file contains the pin mappings for the Waveshare RP2040-PiZero board.
+//
+// Waveshare RP2040-PiZero uses the Raspberry Pi RP2040 chip.
+//
+// - https://www.waveshare.com/wiki/RP2040-PiZero
+// - https://github.com/raspberrypi/pico-sdk/blob/master/src/boards/include/boards/waveshare_rp2040_pizero.h
+package machine
+
+// GPIO pins
+const (
+	GP0  Pin = GPIO0
+	GP1  Pin = GPIO1
+	GP2  Pin = GPIO2
+	GP3  Pin = GPIO3
+	GP4  Pin = GPIO4
+	GP5  Pin = GPIO5
+	GP6  Pin = GPIO6
+	GP7  Pin = GPIO7
+	GP8  Pin = GPIO8
+	GP9  Pin = GPIO9
+	GP10 Pin = GPIO10
+	GP11 Pin = GPIO11
+	GP12 Pin = GPIO12
+	GP13 Pin = GPIO13
+	GP14 Pin = GPIO14
+	GP15 Pin = GPIO15
+	GP16 Pin = GPIO16
+	GP17 Pin = GPIO17
+	GP18 Pin = GPIO18
+	GP19 Pin = GPIO19
+	GP20 Pin = GPIO20
+	GP21 Pin = GPIO21
+	GP22 Pin = GPIO22
+	GP23 Pin = GPIO23
+	GP24 Pin = GPIO24
+	GP25 Pin = GPIO25
+	GP26 Pin = GPIO26
+	GP27 Pin = GPIO27
+	GP28 Pin = GPIO28
+	GP29 Pin = GPIO29
+
+	// The Pico SDK board header defines no default LED pin.
+	LED Pin = NoPin
+
+	// Onboard crystal oscillator frequency, in MHz.
+	xoscFreq = 12 // MHz
+)
+
+// Analog pins
+const (
+	A0 Pin = GP26
+	A1 Pin = GP27
+	A2 Pin = GP28
+	A3 Pin = GP29
+)
+
+// I2C default pins
+const (
+	I2C0_SDA_PIN Pin = NoPin
+	I2C0_SCL_PIN Pin = NoPin
+
+	I2C1_SDA_PIN Pin = GP6
+	I2C1_SCL_PIN Pin = GP7
+)
+
+// SPI default pins
+const (
+	SPI0_RX_PIN  Pin = GP16
+	SPI0_CSN_PIN Pin = GP17
+	SPI0_SCK_PIN Pin = GP18
+	SPI0_TX_PIN  Pin = GP19
+	SPI0_SDO_PIN Pin = SPI0_TX_PIN
+	SPI0_SDI_PIN Pin = SPI0_RX_PIN
+
+	SPI1_SCK_PIN Pin = GP10
+	SPI1_SDO_PIN Pin = GP11
+	SPI1_SDI_PIN Pin = GP12
+)
+
+// UART pins
+const (
+	UART0_TX_PIN = GP0
+	UART0_RX_PIN = GP1
+	UART1_TX_PIN = GP8
+	UART1_RX_PIN = GP9
+	UART_TX_PIN  = UART0_TX_PIN
+	UART_RX_PIN  = UART0_RX_PIN
+)
+
+var DefaultUART = UART0
+
+// USB identifiers
+const (
+	usb_STRING_PRODUCT      = "RP2040-PiZero"
+	usb_STRING_MANUFACTURER = "Waveshare"
+)
+
+var (
+	usb_VID uint16 = 0x2e8a
+	usb_PID uint16 = 0x0003
+)
diff --git a/targets/waveshare-rp2040-pizero.json b/targets/waveshare-rp2040-pizero.json
new file mode 100644
index 000000000..5b7f1653f
--- /dev/null
+++ b/targets/waveshare-rp2040-pizero.json
@@ -0,0 +1,14 @@
+{
+    "inherits": [
+        "rp2040"
+    ],
+    "serial-port": ["2e8a:0003"],
+    "default-stack-size": 8192,
+    "build-tags": ["waveshare_rp2040_pizero"],
+    "ldflags": [
+        "--defsym=__flash_size=16M"
+    ],
+    "extra-files": [
+        "targets/pico-boot-stage2.S"
+    ]
+}