定时器简介
在 ZYNQ 嵌入式系统中,定时器的资源是非常丰富的,每个 Cortex-A9 处理器都有各自独立的 32 位私有定时器和 32 位看门狗定时器,这两个 CPU 同时共享一个 64 位的全局定时器(GT)。
系统框图
私有定时器
特点
- 32 位计数器,当计数器递减至 0 时产生中断
- 8 位预分频计数器,可以更好的控制中断周期
- 可以配置单次定时或者自动重载模式
- 通过配置起始计数值来设置定时时间
时钟
- 私有定时器时钟为 CPU 频率(CPU_3x2x)的一半,如 ARM 的工作时钟频率为 666.666Mhz,则私有定时器的时钟频率为 333.333Mhz。
寄存器表
驱动示例
- timer.c
/*** Copyright (c) 2022-2023,HelloAlpha* * Change Logs:* Date Author Notes*/
#include "timer.h"int TimerInit(XScuTimer *TimerInstancePtr, uint16_t TimerDeviceId, uint32_t TimerLoadValue)
{int Status;XScuTimer_Config *ConfigPtr;ConfigPtr = XScuTimer_LookupConfig(TimerDeviceId);Status = XScuTimer_CfgInitialize(TimerInstancePtr, ConfigPtr,ConfigPtr->BaseAddr);if (Status != XST_SUCCESS) {return XST_FAILURE;}Status = XScuTimer_SelfTest(TimerInstancePtr);if (Status != XST_SUCCESS) {return XST_FAILURE;}XScuTimer_EnableAutoReload(TimerInstancePtr);XScuTimer_LoadTimer(TimerInstancePtr, TimerLoadValue);return Status;
}int TimerIntrInit(XScuGic *IntcInstancePtr, XScuTimer *TimerInstancePtr, uint32_t TimerIntrId, void(* CallBack)(void *))
{int Status;XScuGic_Config *IntcConfig;IntcConfig = XScuGic_LookupConfig(INTC_DEVICE_ID);if (NULL == IntcConfig) {return XST_FAILURE;}Status = XScuGic_CfgInitialize(IntcInstancePtr, IntcConfig,IntcConfig->CpuBaseAddress);if (Status != XST_SUCCESS) {return XST_FAILURE;}Xil_ExceptionInit();Xil_ExceptionRegisterHandler(XIL_EXCEPTION_ID_INT,(Xil_ExceptionHandler)XScuGic_InterruptHandler,IntcInstancePtr);Xil_ExceptionEnable();Status = XScuGic_Connect(IntcInstancePtr, TimerIntrId,(Xil_ExceptionHandler)CallBack, (void *)TimerInstancePtr);if (Status != XST_SUCCESS) {return Status;}XScuGic_Enable(IntcInstancePtr, TimerIntrId);XScuTimer_EnableInterrupt(TimerInstancePtr);return XST_SUCCESS;
}
- timer.h
/*** Copyright (c) 2022-2023,HelloAlpha* * Change Logs:* Date Author Notes*/
#ifndef __TIMER_H__
#define __TIMER_H__#include "xscutimer.h"
#include "xscugic.h"/* CPU时钟频率 */
#ifndef CPU_CLK_FREQ_HZ
#define CPU_CLK_FREQ_HZ XPAR_CPU_CORTEXA9_0_CPU_CLK_FREQ_HZ
#endif/* 私有定时器的时钟频率 = CPU时钟频率/2 = 333MHz */
#define TIMER_HZ CPU_CLK_FREQ_HZ/2#ifndef INTC_DEVICE_ID
#define INTC_DEVICE_ID XPAR_SCUGIC_SINGLE_DEVICE_ID
#endif#define TIMER_DEVICE_ID XPAR_XSCUTIMER_0_DEVICE_ID
#define TIMER_IRPT_INTR XPAR_SCUTIMER_INTR/** Function declaration*/
int TimerInit(XScuTimer *TimerInstancePtr, uint16_t TimerDeviceId, uint32_t TimerLoadValue);
int TimerIntrInit(XScuGic *IntcInstancePtr, XScuTimer *TimerInstancePtr, uint32_t TimerIntrId, void(* CallBack)(void *));#endif
应用示例
- app_timer.c
/*** Copyright (c) 2022-2023,HelloAlpha* * Change Logs:* Date Author Notes*/
#include "app_timer.h"#define USING_ULOG
#include "ulog.h"extern XScuGic IntcInstPtr;/*** @brief 定时器中断处理,中断时间 50ms*/
void TimerIntrHandler(void *CallBackRef)
{XScuTimer *TimerInstancePtr = (XScuTimer *) CallBackRef;struct timer_flag *_timer_flag = &g_timer_flag;static uint16_t count = 0;/* 标志位触发 */
// XScuTimer_IsExpired(TimerInstancePtr);ULOG("--- timer handle --- \r\n");count++;if(count == 101){count = 0;}ULOG("count: %d\r\n", count);_timer_flag->timer_flag_50ms = 1;if(count % 10 == 0){_timer_flag->timer_flag_500ms = 1;ULOG("--- 500 MS --- \r\n");}if(count % 20 == 0){_timer_flag->timer_flag_1s = 1;ULOG("--- 1 S --- \r\n");}XScuTimer_ClearInterruptStatus(TimerInstancePtr);/* 关闭自动重装载值 关闭中断 */// XScuTimer_DisableAutoReload(TimerInstancePtr);
}int app_timer_init(void)
{int Status;Status = TimerInit(&Timer, TIMER_DEVICE_ID, TIMER_LOAD_VALUE);if (Status != XST_SUCCESS) {return XST_FAILURE;}Status = TimerIntrInit(&IntcInstPtr, &Timer, TIMER_IRPT_INTR, TimerIntrHandler);if (Status != XST_SUCCESS) {return XST_FAILURE;}XScuTimer_Start(&Timer);return Status;
}
- app_timer.h
/*** Copyright (c) 2022-2023,HelloAlpha* * Change Logs:* Date Author Notes*/
#ifndef __APP_TIMER_H__
#define __APP_TIMER_H__#include "timer.h"/* CPU时钟频率 */
#ifndef CPU_CLK_FREQ_HZ
#define CPU_CLK_FREQ_HZ XPAR_CPU_CORTEXA9_0_CPU_CLK_FREQ_HZ
#endif/* 私有定时器的时钟频率 = CPU时钟频率/2 = 333MHz */
#define TIMER_HZ CPU_CLK_FREQ_HZ/2/** 精确计算 装载值 = 定时时间(单位:秒)* 333333333* 0.5s 166,666,666.5 0x9EF21AA* 0.1s 333,333,33.3 0x1FCA055* 0.05s 16,666,666,65 0xFE502A*/
#define TIMER_LOAD_VALUE 0xFE502AXScuTimer Timer;struct timer_flag
{char timer_flag_50ms;char timer_flag_500ms;char timer_flag_1s;
};typedef struct timer_flag timer_flag_t;timer_flag_t g_timer_flag;int app_timer_init(void);#endif
测试平台:黑金 AC7Z035B
芯片型号:XC7Z035-2FFG676
参考来源:UG585