From f5e933cd4d418b0dffdbc4e795a417026ced778a Mon Sep 17 00:00:00 2001
From: Xudong Zheng <7pkvm5aw@slicealias.com>
Date: Thu, 1 Feb 2024 12:54:58 -0500
Subject: machine/rp2040: set XOSC startup delay multiplier

XOSC requires additional time to stablize on certain RP2040 boards.

Signed-off-by: Xudong Zheng <7pkvm5aw@slicealias.com>
---
 src/machine/machine_rp2040_xosc.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/machine/machine_rp2040_xosc.go b/src/machine/machine_rp2040_xosc.go
index c3d6d713a..0acac1f1e 100644
--- a/src/machine/machine_rp2040_xosc.go
+++ b/src/machine/machine_rp2040_xosc.go
@@ -8,6 +8,11 @@ import (
 	"unsafe"
 )
 
+// On some boards, the XOSC can take longer than usual to stabilize. On such
+// boards, this is needed to avoid a hard fault on boot/reset. Refer to
+// PICO_XOSC_STARTUP_DELAY_MULTIPLIER in the Pico SDK for additional details.
+const XOSC_STARTUP_DELAY_MULTIPLIER = 64
+
 type xoscType struct {
 	ctrl     volatile.Register32
 	status   volatile.Register32
@@ -30,7 +35,7 @@ func (osc *xoscType) init() {
 	osc.ctrl.Set(rp.XOSC_CTRL_FREQ_RANGE_1_15MHZ)
 
 	// Set xosc startup delay
-	delay := (((xoscFreq * MHz) / 1000) + 128) / 256
+	delay := (((xoscFreq * MHz) / 1000) + 128) / 256 * XOSC_STARTUP_DELAY_MULTIPLIER
 	osc.startup.Set(uint32(delay))
 
 	// Set the enable bit now that we have set freq range and startup delay
-- 
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