工程搭建参考：https://blog.csdn.net/feisy/article/details/126380289

F28069有三个32位的CPU定时器：0,1,2。0，1可用，如果程序未使用DIS/BIOS，定时器2也可用。

CPU定时器相关的有5个信号，四个输入信号，一个输出信号

1. Reset信号：复位信号，给定时器复位用的
2. Timer reload:定时器重载信号，控制定时器要不要重新装载周期计算器
3. SYSCLKOUT:系统时钟信号
4. TCR.4=TCR.bit.4.TSS:控制定时器计时开始或者停止
5. TINT:输出信息，周期中断

CPU定时器涉及的寄存器

1. TDDR :定时器减一的时间长度，两个16位的寄存器表示
2. PRD：设置CPU定时器的周期，两个16位的寄存器表示
3. PSC开始计数时，会将TDDR 装载到这里，用来不断自减减到0,到0会产生TIMCLK信号，让TIM减一
4. TIM：开始计数时，会将PRD 装载到这里，用来不断自减，，会产生一个中断信号，这时会回调定时器中断函数
5. TPR：F28069里跟TDDR功能一样的寄存器？
6. TCR：装载，启用或者停止定时器的寄存器：TCR.bit.TSS = 1（1 = Stop timer, 0 = Start/Restart Timer），TCR.bit.TRB = 1（ 1 = reload timer），TCR.bit.TIE = 1（ 0 = Disable/ 1 = Enable Timer Interrupt）

定时器的寄存器的形式是XH:X这样的形式，后半部分X表示低位，前半部分XH表示高位

#CPU定时器的工作原理

1. 给CPU周期寄存器赋值
   

2. 开始计数时，CPU会将计数值装在到TIM寄存器
   

3. 每个一个TIMCLK，TIM会不断减一，一直减到0
   

4. 减到0，完成一个定时周期，会产生一个中断
   .

TIMCLK代表是了计数器减一的时间长度，它是通过定时器 的分频寄存器TDDR来设置的

计数时，TIMCLK会被装载到PSC寄存器

PSC里面的数值在每个SYSCLK都会减一，减到0时，会产生一个让TIMCLK减一的信号

一个计算例子
PDR会被装载到PSC,每个SYSCLK都会减一，减到0时，会产生一个让TIMCLK减一的信号,TIMCLK=(1+PDR)个SYSCLKOUT,以F28335为例，主频是150M,TIMCLK=(1+PDR)*(1/150M)秒

一个周期是 (1+PRD) * TIMCLK

代码演示，通过定时器来控制LED闪烁

1 设置定时器的回调函数

注意，TINT0是在PIE TABLE的第7位，后面还有关于启用第一组，以及启用第7个中断的设置

// Interrupts that are used in this example are re-mapped to
// ISR functions found within this file.EALLOW;  // This is needed to write to EALLOW protected registersPieVectTable.TINT0 = &cpu_timer0_isr;EDIS;    // This is needed to disable write to EALLOW protected registers

2 获取定时器寄存器， 配置定时器的一些默认值

使用到的一个函数

void InitCpuTimers(void)
{// CPU Timer 0// Initialize address pointers to respective timer registers:CpuTimer0.RegsAddr = &CpuTimer0Regs;// Initialize timer period to maximum:CpuTimer0Regs.PRD.all  = 0xFFFFFFFF;//PRD寄存器设置CPU定时器的周期，两个16位的寄存器表示，这里设置到最大//TPR寄存器的作用是CPU会在(TPR[TDDRH:TDDR]+1)个SYSCLOUT后，将TIM减一,这里置0，表示，每个SYSCLKOUT都会让TIM减一// Initialize pre-scale counter to divide by 1 (SYSCLKOUT)://The 32-bit counter register TIMH:TIM is loaded with//the value in the period register PRDH:PRD. The counter decrements once every (TPR[TDDRH:TDDR]+1)SYSCLKOUT cycles, where TDDRH:TDDR is the timer divider. CpuTimer0Regs.TPR.all  = 0;CpuTimer0Regs.TPRH.all = 0;// Make sure timer is stopped:CpuTimer0Regs.TCR.bit.TSS = 1;//TSS=0表示定时器停止// Reload all counter register with period value:CpuTimer0Regs.TCR.bit.TRB = 1;// Reset interrupt counters://CpuTimer0.InterruptCount = 0;// Initialize address pointers to respective timer registers:CpuTimer1.RegsAddr = &CpuTimer1Regs;CpuTimer2.RegsAddr = &CpuTimer2Regs;// Initialize timer period to maximum:CpuTimer1Regs.PRD.all  = 0xFFFFFFFF;CpuTimer2Regs.PRD.all  = 0xFFFFFFFF;// Initialize pre-scale counter to divide by 1 (SYSCLKOUT):CpuTimer1Regs.TPR.all  = 0;CpuTimer1Regs.TPRH.all = 0;CpuTimer2Regs.TPR.all  = 0;CpuTimer2Regs.TPRH.all = 0;// Make sure timers are stopped:CpuTimer1Regs.TCR.bit.TSS = 1;CpuTimer2Regs.TCR.bit.TSS = 1;// Reload all counter register with period value:CpuTimer1Regs.TCR.bit.TRB = 1;CpuTimer2Regs.TCR.bit.TRB = 1;// Reset interrupt counters://CpuTimer1.InterruptCount = 0;//CpuTimer2.InterruptCount = 0;}

3 设置定时器的长度

因为F28069的主频是80M，所以我们设置定时器的周期步数是80，每一步是1000000，即1000000个SYSCLKOUT，定时器减一。

// Configure CPU-Timer 0, 1, and 2 to interrupt every second:
// 80MHz CPU Freq, 1 second Period (in uSeconds)ConfigCpuTimer(&CpuTimer0, 80, 1000000);

void ConfigCpuTimer(struct CPUTIMER_VARS *Timer, float Freq, float Period)
{Uint32 	PeriodInClocks;// Initialize timer period:Timer->CPUFreqInMHz = Freq;Timer->PeriodInUSec = Period;PeriodInClocks = (long) (Freq * Period);//设置CPU定时器的周期，Timer->RegsAddr->PRD.all = PeriodInClocks - 1; // Counter decrements PRD+1 times each period//这里这样的设置是每个SYSCLKOUT，都会产生一个TIMCLK，让其减一// Set pre-scale counter to divide by 1 (SYSCLKOUT):Timer->RegsAddr->TPR.all  = 0;Timer->RegsAddr->TPRH.all  = 0;// Initialize timer control register:Timer->RegsAddr->TCR.bit.TSS = 1;      // 1 = Stop timer, 0 = Start/Restart TimerTimer->RegsAddr->TCR.bit.TRB = 1;      // 1 = reload timerTimer->RegsAddr->TCR.bit.SOFT = 0;Timer->RegsAddr->TCR.bit.FREE = 0;     // Timer Free Run DisabledTimer->RegsAddr->TCR.bit.TIE = 1;      // 0 = Disable/ 1 = Enable Timer Interrupt// Reset interrupt counter:Timer->InterruptCount = 0;}

4 启用定时器

	//TCR.bit.TSS = 0表示启动寄存器CpuTimer0Regs.TCR.all = 0x4000; // Use write-only instruction to set TSS bit = 0

5 启用 中断向量表的第一组

    //// Enable CPU INT1 which is connected to CPU-Timer 0//IER |= M_INT1;

6 启用 中断向量表的第一组的第7个中断

    //// Enable TINT0 in the PIE: Group 1 interrupt 7//PieCtrlRegs.PIEIER1.bit.INTx7 = 1;

7 打开全局中断

// Enable global Interrupts and higher priority real-time debug events:EINT;   // Enable Global interrupt INTMERTM;   // Enable Global realtime interrupt DBGM

5 完整代码

//###########################################################################
//
// FILE:   Example_2806xLEDBlink.c
//
// TITLE:  Timer based blinking LED Example
//
//!  \addtogroup f2806x_example_list
//!  
Timer based blinking LED(timed_led_blink)
//!
//!  This example configures CPU Timer0 for a 500 msec period, and toggles the
//!  GPIO34 LED once per interrupt. For testing purposes, this example
//!  also increments a counter each time the timer asserts an interrupt.
//!
//!  \b Watch \b Variables \n
//!  - CpuTimer0.InterruptCount
//!
//! \b External \b Connections \n
//!  Monitor the GPIO34 LED blink on (for 500 msec) and off (for 500 msec) on
//!  the 2806x control card.
//
//###########################################################################
// $TI Release:  $
// $Release Date:  $
// $Copyright:
// Copyright (C) 2009-2022 Texas Instruments Incorporated - http://www.ti.com/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
//   Redistributions of source code must retain the above copyright
//   notice, this list of conditions and the following disclaimer.
//
//   Redistributions in binary form must reproduce the above copyright
//   notice, this list of conditions and the following disclaimer in the
//   documentation and/or other materials provided with the
//   distribution.
//
//   Neither the name of Texas Instruments Incorporated nor the names of
//   its contributors may be used to endorse or promote products derived
//   from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// $
//###########################################################################//
// Included Files
//
#include "DSP28x_Project.h"     // Device Headerfile and Examples Include File//
// Function Prototypes statements for functions found within this file.
//
__interrupt void cpu_timer0_isr(void);//
// Main
//
void main(void)
{//// Step 1. Initialize System Control:// PLL, WatchDog, enable Peripheral Clocks// This example function is found in the F2806x_SysCtrl.c file.//InitSysCtrl();//// Step 2. Initalize GPIO:// This example function is found in the F2806x_Gpio.c file and// illustrates how to set the GPIO to it's default state.//
//    InitGpio();  // Skipped for this example//// Step 3. Clear all interrupts and initialize PIE vector table:// Disable CPU interrupts//DINT;//// Initialize the PIE control registers to their default state.// The default state is all PIE interrupts disabled and flags// are cleared.// This function is found in the F2806x_PieCtrl.c file.//InitPieCtrl();//// Disable CPU interrupts and clear all CPU interrupt flags//IER = 0x0000;IFR = 0x0000;//// Initialize the PIE vector table with pointers to the shell Interrupt// Service Routines (ISR).// This will populate the entire table, even if the interrupt// is not used in this example.  This is useful for debug purposes.// The shell ISR routines are found in F2806x_DefaultIsr.c.// This function is found in F2806x_PieVect.c.//InitPieVectTable();//// Interrupts that are used in this example are re-mapped to// ISR functions found within this file.//EALLOW;    // This is needed to write to EALLOW protected registersPieVectTable.TINT0 = &cpu_timer0_isr;EDIS;      // This is needed to disable write to EALLOW protected registers//// Step 4. Initialize the Device Peripheral. This function can be//         found in F2806x_CpuTimers.c//InitCpuTimers();   // For this example, only initialize the Cpu Timers//// Configure CPU-Timer 0 to interrupt every 500 milliseconds:// 80MHz CPU Freq, 50 millisecond Period (in uSeconds)//ConfigCpuTimer(&CpuTimer0, 80, 500000);//// To ensure precise timing, use write-only instructions to write to the// entire register. Therefore, if any of the configuration bits are changed// in ConfigCpuTimer and InitCpuTimers (in F2806x_CpuTimers.h), the// below settings must also be updated.////// Use write-only instruction to set TSS bit = 0//CpuTimer0Regs.TCR.all = 0x4001;//// Step 5. User specific code, enable interrupts:////// Configure GPIO34 as a GPIO output pin//EALLOW;GpioCtrlRegs.GPBMUX1.bit.GPIO34 = 0;GpioCtrlRegs.GPBDIR.bit.GPIO34 = 1;EDIS;//// Enable CPU INT1 which is connected to CPU-Timer 0//IER |= M_INT1;//// Enable TINT0 in the PIE: Group 1 interrupt 7//PieCtrlRegs.PIEIER1.bit.INTx7 = 1;//// Enable global Interrupts and higher priority real-time debug events//EINT;   // Enable Global interrupt INTMERTM;   // Enable Global realtime interrupt DBGM//// Step 6. IDLE loop. Just sit and loop forever (optional)//for(;;);
}//
// cpu_timer0_isr -
//
__interrupt void
cpu_timer0_isr(void)
{CpuTimer0.InterruptCount++;//// Toggle GPIO34 once per 500 milliseconds////我之前一直用软件的角度去看代码，以为这个是赋值的意思，但其实这个是硬件中的GPIO的翻转操作//，即每次=1,会让GPIO的电平发生变化，变到另外一个状态。//比如，原先是高电平，执行一次=1，就变成了低电平了。。。。GpioDataRegs.GPBTOGGLE.bit.GPIO34 = 1;//// Acknowledge this interrupt to receive more interrupts from group 1//PieCtrlRegs.PIEACK.all = PIEACK_GROUP1;
}//
// End of File
//