add arduino uno board

build.zig

@@ -17,6 +17,7 @@ pub fn build(b: *std.build.Builder) !void {
     const BuildConfig = struct { name: []const u8, backing: Backing, supports_uart_test: bool = true };
     const all_backings = [_]BuildConfig{
         BuildConfig{ .name = "boards.arduino_nano", .backing = Backing{ .board = boards.arduino_nano } },
+        BuildConfig{ .name = "boards.arduino_uno", .backing = Backing{ .board = boards.arduino_uno } },
         BuildConfig{ .name = "boards.mbed_lpc1768", .backing = Backing{ .board = boards.mbed_lpc1768 } },
         BuildConfig{ .name = "chips.atmega328p", .backing = Backing{ .chip = chips.atmega328p } },
         BuildConfig{ .name = "chips.lpc1768", .backing = Backing{ .chip = chips.lpc1768 } },

src/modules/boards.zig

@@ -14,6 +14,12 @@ pub const arduino_nano = Board{
     .chip = chips.atmega328p,
 };
 
+pub const arduino_uno = Board{
+    .name = "Arduino Uno",
+    .path = root_path ++ "boards/arduino-uno/arduino-uno.zig",
+    .chip = chips.atmega328p,
+};
+
 pub const mbed_lpc1768 = Board{
     .name = "mbed LPC1768",
     .path = root_path ++ "boards/mbed-lpc1768/mbed-lpc1768.zig",

src/modules/boards/arduino-uno/arduino-uno.zig

@@ -0,0 +1,32 @@
+pub const chip = @import("chip");
+
+pub const clock_frequencies = .{
+    .cpu = 16_000_000,
+};
+
+pub const pin_map = .{
+    // Port D
+    .D0 = "PD0",
+    .D1 = "PD1",
+    .D2 = "PD2",
+    .D3 = "PD3",
+    .D4 = "PD4",
+    .D5 = "PD5",
+    .D6 = "PD6",
+    .D7 = "PD7",
+    // Port B
+    .D8 = "PB0",
+    .D9 = "PB1",
+    .D10 = "PB2",
+    .D11 = "PB3",
+    .D12 = "PB4",
+    // LED_BUILTIN
+    .D13 = "PB5",
+    // Port C (Analog)
+    .A0 = "PC0",
+    .A1 = "PC1",
+    .A2 = "PC2",
+    .A3 = "PC3",
+    .A4 = "PC4",
+    .A5 = "PC5",
+};

src/modules/chips/atmega328p/atmega328p.zig

@@ -106,7 +106,7 @@ pub fn Uart(comptime index: usize, comptime pins: micro.uart.Pins) type {
             const pclk = micro.clock.get().cpu;
             const divider = ((pclk + (8 * baud_rate)) / (16 * baud_rate)) - 1;
 
-            return std.math.cast(u12, divider) catch return error.UnsupportedBaudRate;
+            return std.math.cast(u12, divider) orelse return error.UnsupportedBaudRate;
         }
 
         fn computeBaudRate(divider: u12) u32 {

tests/blinky.zig

@@ -4,6 +4,7 @@ const micro = @import("microzig");
 const led_pin = if (micro.config.has_board)
     switch (micro.config.board_name) {
         .@"Arduino Nano" => micro.Pin("D13"),
+        .@"Arduino Uno" => micro.Pin("D13"),
         .@"mbed LPC1768" => micro.Pin("LED-1"),
         .@"STM32F3DISCOVERY" => micro.Pin("LD3"),
         .@"STM32F4DISCOVERY" => micro.Pin("LD5"),

tests/uart-sync.zig

@@ -23,6 +23,11 @@ const cfg = if (micro.config.has_board)
             .uart_idx = 1,
             .pins = .{ .tx = null, .rx = null },
         },
+        .@"Arduino Uno" => .{
+            .led_pin = micro.Pin("D13"),
+            .uart_idx = 0,
+            .pins = .{},
+        },
         else => @compileError("unknown board"),
     }
 else switch (micro.config.chip_name) {