Set startup_delay_multiplier of XOSC to 64

rp2040-hal/CHANGELOG.md

@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
 
 - bump MSRV to 1.65
+- Set startup\_delay\_multiplier of XOSC to 64, and make it configurable.
+  This should increase compatibility with boards where the oscillator starts up
+  more slowly than on the Raspberry Pico.
 
 ## [0.9.1]
 

rp2040-hal/src/xosc.rs

@@ -49,11 +49,36 @@ pub enum Error {
 }
 
 /// Blocking helper method to setup the XOSC without going through all the steps.
+///
+/// This uses a startup_delay_multiplier of 64, which is a rather conservative value
+/// that should work even if the XOSC starts up slowly. In case you need a fast boot
+/// sequence, and your XOSC starts up quickly enough, use [`setup_xosc_blocking_custom_delay`].
 pub fn setup_xosc_blocking(
     xosc_dev: XOSC,
     frequency: HertzU32,
 ) -> Result<CrystalOscillator<Stable>, Error> {
-    let initialized_xosc = CrystalOscillator::new(xosc_dev).initialize(frequency, 1)?;
+    let initialized_xosc = CrystalOscillator::new(xosc_dev).initialize(frequency, 64)?;
+
+    let stable_xosc_token = nb::block!(initialized_xosc.await_stabilization()).unwrap();
+
+    Ok(initialized_xosc.get_stable(stable_xosc_token))
+}
+
+/// Blocking helper method to setup the XOSC without going through all the steps.
+///
+/// This function allows setting a startup_delay_multiplier to tune the amount of time
+/// the chips waits for the XOSC to stabilize.
+/// The default value in the C SDK is 1, which should work on the Raspberry Pico, and many
+/// third-party boards.
+/// [`setup_xosc_blocking`], uses a conservative value of 64, which is the value commonly
+/// used on slower-starting oscillators.
+pub fn setup_xosc_blocking_custom_delay(
+    xosc_dev: XOSC,
+    frequency: HertzU32,
+    startup_delay_multiplier: u32,
+) -> Result<CrystalOscillator<Stable>, Error> {
+    let initialized_xosc =
+        CrystalOscillator::new(xosc_dev).initialize(frequency, startup_delay_multiplier)?;
 
     let stable_xosc_token = nb::block!(initialized_xosc.await_stabilization()).unwrap();