武林教你学PIC32（五）定时器

今天我们用定时器实现LED灯的1s闪烁。

首先我们看看要用的几个库函数：

1 OpenTimer1配置16位定时器函数，函数定义为：

void OpenTimer1(unsigned int config,unsigned int period);

参数有：

Timer Module On/Off

Tx_ON

Tx_OFF

(These bit fields are mutually exclusive)

Asynchronous Timer Write Disable

T1_TMWDIS_ON

T1_TMWDIS_OFF

(These bit fields are mutually exclusive)

Timer Module Idle mode On/Off

Tx_IDLE_CON

Tx_IDLE_STOP

(These bit fields are mutually exclusive)

Timer Gate time accumulation enable

Tx_GATE_ON

Tx_GATE_OFF

(These bit fields are mutually exclusive)

Timer Prescaler(1)

T1_PS_1_1

T1_PS_1_8

T1_PS_1_64

T1_PS_1_256

Timer Prescaler

Tx_PS_1_1

Tx_PS_1_2

Tx_PS_1_4

Tx_PS_1_8

Tx_PS_1_16

Tx_PS_1_32

Tx_PS_1_64

Tx_PS_1_256

(These bit fields are mutually exclusive)

Timer Synchronous clock enable(1)

Tx_SYNC_EXT_ON

(These bit fields are mutually exclusive)

Timer Clock source

Tx_SOURCE_EXT

(These bit fields are mutually exclusive)

我需要设置的是T1_ON（开启TIMER1模块）、T1_SOURCE_INT（内部时钟）、T1_PS_1_256（256分频）和period（初值）

2ConfigIntTimer1设置定时器1的中断，函数原型为：

void ConfigIntTimer1(unsigned int config);

Timer interrupt enable/disable

Tx_INT_ON

Tx_INT_OFF

(These bit fields are mutually exclusive)

Timer interrupt priorities

Tx_INT_PRIOR_7

Tx_INT_PRIOR_6

Tx_INT_PRIOR_5

Tx_INT_PRIOR_4

Tx_INT_PRIOR_3

Tx_INT_PRIOR_2

Tx_INT_PRIOR_1

Tx_INT_PRIOR_0

(These bit fields are mutually exclusive)

Timer interrupt sub- priorities

Tx_INT_SUB_PRIOR_3

Tx_INT_SUB_PRIOR_2

Tx_INT_SUB_PRIOR_1

Tx_INT_SUB_PRIOR_0

(These bit fields are mutually exclusive)

这里我们设置T1_INT_ON（开中断）和T1_INT_PRIOR_2（2优先级）

3定时器的中断函数

void __ISR(_TIMER_1_VECTOR, ipl2) Timer1Handler(void)

{

//清除中断

mT1ClearIntFlag();

//LED1闪烁

mPORTBToggleBits(BIT_10);

}

还记得第四讲的时钟配置吧，我们这里把系统时钟配置为80M，外设时钟配置为10M，具体配置如图：

我们算算定时1s，TIME1的初值怎么算？应该是外设时钟10M/256