From bfa4501cd703149f4720a4ef6cdbe74ef6c3e361 Mon Sep 17 00:00:00 2001
From: Ian McIntyre <me@mciantyre.dev>
Date: Sun, 30 Aug 2026 17:35:22 -0400
Subject: Add RP2040 support

---
 crates/rp-pico-2040/src/lib.rs | 94 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 crates/rp-pico-2040/src/lib.rs

(limited to 'crates/rp-pico-2040/src/lib.rs')

diff --git a/crates/rp-pico-2040/src/lib.rs b/crates/rp-pico-2040/src/lib.rs
new file mode 100644
index 0000000..8f877aa
--- /dev/null
+++ b/crates/rp-pico-2040/src/lib.rs
@@ -0,0 +1,94 @@
+//! Standard library support crate for an Raspberry Pi Pico with an RP2040.
+//!
+//! The blinky support example comes from the rp-hal-boards example, available
+//! <https://github.com/rp-rs/rp-hal-boards/blob/5135e3dafe3e69b112e6d2d72cfb1856a7679b82/boards/rp-pico/examples/pico_blinky.rs#L1>
+//! and licensed MIT or APACHE-2.0.
+
+#![no_std]
+#![feature(rustc_private)]
+extern crate fusible;
+
+use core::pin::Pin;
+
+use rust_threadx_cortex_m as _;
+use rust_threadx_stdio_semihosting as _;
+use rust_threadx_sync_single_core as _;
+
+use embedded_hal::digital::OutputPin;
+use rp_pico::hal;
+use rp_pico::hal::pac;
+
+#[doc(hidden)]
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn _tx_initialize_low_level() {
+    use cortex_m::{
+        Peripherals,
+        peripheral::{scb::SystemHandler, syst::SystClkSource},
+    };
+
+    cortex_m::interrupt::disable();
+
+    unsafe {
+        let Peripherals {
+            mut SYST, mut SCB, ..
+        } = Peripherals::steal();
+
+        SCB.set_priority(SystemHandler::SysTick, 0x40);
+        SCB.set_priority(SystemHandler::PendSV, 0xff);
+        SCB.set_priority(SystemHandler::SVCall, 0xff);
+
+        SYST.set_clock_source(SystClkSource::Core);
+        SYST.set_reload(125_000_000 / 100 - 1);
+        SYST.clear_current();
+        SYST.enable_interrupt();
+        SYST.enable_counter();
+    }
+}
+
+use fusible::thread::{StaticStack, Thread, ThreadContext};
+static STACK: StaticStack<512> = StaticStack::new();
+static THREAD: ThreadContext = Thread::context();
+
+#[unsafe(no_mangle)]
+#[doc(hidden)]
+pub extern "C" fn __rust_threadx_app_define() {
+    let mut pac = pac::Peripherals::take().unwrap();
+
+    let mut watchdog = hal::Watchdog::new(pac.WATCHDOG);
+
+    hal::clocks::init_clocks_and_plls(
+        rp_pico::XOSC_CRYSTAL_FREQ,
+        pac.XOSC,
+        pac.CLOCKS,
+        pac.PLL_SYS,
+        pac.PLL_USB,
+        &mut pac.RESETS,
+        &mut watchdog,
+    )
+    .ok()
+    .unwrap();
+
+    let sio = hal::Sio::new(pac.SIO);
+
+    let pins = rp_pico::Pins::new(
+        pac.IO_BANK0,
+        pac.PADS_BANK0,
+        sio.gpio_bank0,
+        &mut pac.RESETS,
+    );
+
+    let mut led_pin = pins.led.into_push_pull_output();
+
+    Thread::create(
+        Pin::static_ref(&THREAD),
+        STACK.take().unwrap(),
+        &Default::default(),
+        move || loop {
+            led_pin.set_high().unwrap();
+            fusible::thread::sleep(50);
+            led_pin.set_low().unwrap();
+            fusible::thread::sleep(50);
+        },
+    )
+    .unwrap();
+}
-- 
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