From 7df5ddf72cd8226efbdf127721bbe14bf1cfccc2 Mon Sep 17 00:00:00 2001
From: Eric Brombaugh <ebrombaugh1@cox.net>
Date: Mon, 24 Apr 2023 12:42:32 -0700
Subject: [PATCH] Updated for latest SysTick changes in ch32v003fun library.
---
examples/systick_irq/README.md | 10 +++++-----
examples/systick_irq/systick_irq.c | 3 +++
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/examples/systick_irq/README.md b/examples/systick_irq/README.md
index 732b29b..26e561e 100644
--- a/examples/systick_irq/README.md
+++ b/examples/systick_irq/README.md
@@ -4,11 +4,11 @@ interrupts for timing. Many bare-metal and RTOS based embedded applications will
use the Systick IRQ for timing, periodic housekeeping and task arbitration so
knowing how to set that up is useful.
-Note that this example is *NOT* compatible with the Delay_Ms() function that's
-part of the ch32v003fun library - that function uses the Systick counter for
-doing busy-wait delays and will interfere with its use in generating predictable
-IRQs. Do not use the built-in Delay_Ms() and related functions when using Systick
-for IRQs.
+Note that this example is *NOT* compatible with the Delay_*() functions that are
+part of the ch32v003fun library - those functions use the Systick counter for
+doing busy-wait delays and assume that the CNT register rolls over at 32-bit
+maximum. Do not use the built-in Delay_Ms() and related functions when using
+Systick for IRQs.
Note also the use of the `__attribute__((interrupt))` syntax in declaring the
IRQ handler. Some of the IRQ examples from the WCH HAL library have slightly
diff --git a/examples/systick_irq/systick_irq.c b/examples/systick_irq/systick_irq.c
index 0ec6631..6091b1e 100644
--- a/examples/systick_irq/systick_irq.c
+++ b/examples/systick_irq/systick_irq.c
@@ -25,6 +25,9 @@ volatile uint32_t systick_cnt;
*/
void systick_init(void)
{
+ /* disable default SysTick behavior */
+ SysTick->CTLR = 0;
+
/* enable the SysTick IRQ */
NVIC_EnableIRQ(SysTicK_IRQn);
--
GitLab