今天我們用定時器實現(xiàn)LED燈的1s閃爍。

首先我們看看要用的幾個庫函數(shù)：

1 OpenTimer1配置16位定時器函數(shù)，函數(shù)定義為：

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

參數(shù)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)

我需要設置的是T1_ON（開啟TIMER1模塊）、T1_SOURCE_INT（內部時鐘）、T1_PS_1_256（256分頻）和period（初值）

2ConfigIntTimer1設置定時器1的中斷，函數(shù)原型為：

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)

這里我們設置T1_INT_ON（開中斷）和T1_INT_PRIOR_2（2優(yōu)先級）

3定時器的中斷函數(shù)

void __ISR(_TIMER_1_VECTOR, ipl2) Timer1Handler(void)

{

//清除中斷

mT1ClearIntFlag();

//LED1閃爍

mPORTBToggleBits(BIT_10);

}

還記得第四講的時鐘配置吧，我們這里把系統(tǒng)時鐘配置為80M，外設時鐘配置為10M，具體配置如圖：

我們算算定時1s，TIME1的初值怎么算？應該是外設時鐘10M/256