From 05c5e405ac10dfa55136c8d0c965811459397618 Mon Sep 17 00:00:00 2001
From: CNLohr <lohr85@gmail.com>
Date: Fri, 12 May 2023 03:14:48 -0400
Subject: [PATCH] Update systick examples to reflect new sysclk usage.
---
examples/systick_irq/Makefile | 2 --
examples/systick_irq/systick_irq.c | 46 ++++++++++++------------------
2 files changed, 19 insertions(+), 29 deletions(-)
diff --git a/examples/systick_irq/Makefile b/examples/systick_irq/Makefile
index 42b59e6..afac4cd 100644
--- a/examples/systick_irq/Makefile
+++ b/examples/systick_irq/Makefile
@@ -2,8 +2,6 @@ all : flash
TARGET:=systick_irq
-CFLAGS+=-DSTDOUT_UART
-
include ../../ch32v003fun/ch32v003fun.mk
flash : cv_flash
diff --git a/examples/systick_irq/systick_irq.c b/examples/systick_irq/systick_irq.c
index 6091b1e..352f4d5 100644
--- a/examples/systick_irq/systick_irq.c
+++ b/examples/systick_irq/systick_irq.c
@@ -1,10 +1,12 @@
/*
* Example for using SysTick with IRQs
* 03-25-2023 E. Brombaugh
+ * 05-12-2023 C. Lohr (Modified to reflect updated sysclk)
*/
// Could be defined here, or in the processor defines.
#define SYSTEM_CORE_CLOCK 48000000
+#define SYSTICK_USE_HCLK
#define APB_CLOCK SYSTEM_CORE_CLOCK
#include "ch32v003fun.h"
@@ -31,9 +33,6 @@ void systick_init(void)
/* enable the SysTick IRQ */
NVIC_EnableIRQ(SysTicK_IRQn);
- /* Clear any existing IRQ */
- SysTick->SR &= ~SYSTICK_SR_CNTIF;
-
/* Set the tick interval to 1ms for normal op */
SysTick->CMP = (SYSTEM_CORE_CLOCK/1000)-1;
@@ -41,9 +40,9 @@ void systick_init(void)
SysTick->CNT = 0;
systick_cnt = 0;
- /* Enable SysTick counter, IRQ, HCLK/1, auto reload */
- SysTick->CTLR = SYSTICK_CTLR_STE | SYSTICK_CTLR_STIE |
- SYSTICK_CTLR_STCLK | SYSTICK_CTLR_STRE;
+ /* Enable SysTick counter, IRQ, HCLK/1 */
+ SysTick->CTLR = SYSTICK_CTLR_STE | SYSTICK_CTLR_STIE |
+ SYSTICK_CTLR_STCLK;
}
/*
@@ -53,25 +52,19 @@ void systick_init(void)
void SysTick_Handler(void) __attribute__((interrupt));
void SysTick_Handler(void)
{
+ // move the compare further ahead in time.
+ // as a warning, if more than this length of time
+ // passes before triggering, you may miss your
+ // interrupt.
+ SysTick->CMP += (SYSTEM_CORE_CLOCK/1000);
+
/* clear IRQ */
- SysTick->SR &= 0;
-
+ SysTick->SR = 0;
+
/* update counter */
systick_cnt++;
}
-/*
- * Millisecond delay routine
- */
-void systick_delay_ms(uint32_t milliseconds)
-{
- /* compute end time */
- uint32_t etime = systick_cnt + milliseconds;
-
- /* wait for current time == end time */
- while(systick_cnt != etime);
-}
-
/*
* entry
*/
@@ -81,8 +74,7 @@ int main()
SystemInit48HSI();
- // start serial @ default 115200bps
- SetupUART( UART_BRR );
+ SetupDebugPrintf();
printf("\r\r\n\nsystick_irq example\n\r");
// init systick @ 1ms rate
@@ -109,13 +101,13 @@ int main()
while(1)
{
GPIOD->BSHR = 1 | (1<<4); // Turn on GPIOs
- systick_delay_ms( 250 );
+ Delay_Ms( 250 );
GPIOC->BSHR = 1;
- systick_delay_ms( 250 );
+ Delay_Ms( 250 );
GPIOD->BSHR = (1<<16) | (1<<(16+4)); // Turn off GPIODs
- systick_delay_ms( 250 );
+ Delay_Ms( 250 );
GPIOC->BSHR = (1<<16);
- systick_delay_ms( 250 );
- printf( "Count: %lu\n\r", count++ );
+ Delay_Ms( 250 );
+ printf( "Count: %lu / Milliseconds: %lu\n\r", count++, systick_cnt );
}
}
--
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