msp430x22x4_ta_09.c

来自「MSP430的开发程序的例子+中文注释」· C语言 代码 · 共 25 行

//******************************************************************************
//  MSP430F22x4 Demo - Timer_A, Toggle P1.0-3, Cont. Mode ISR, HF XTAL ACLK
//
//  Description: Use Timer_A CCRx units and overflow to generate four
//  independent timing intervals. For demonstration, TACCR0, TACCR1 and TACCR2
//  output units are optionally selected with port pins P1.1, P1.2 and P1.3
//  in toggle mode. As such, these pins will toggle when respective TACCRx
//  registers match the TAR counter. Interrupts are also enabled with all
//  TACCRx units, software loads offset to next interval only - as long as the
//  interval offset is added to TACCRx, toggle rate is generated in hardware.
//  Timer_A overflow ISR is used to toggle P1.0 with software. Proper use
//  of the TAIV interrupt vector generator is demonstrated.
//  ACLK = MCLK = TACLK = LFXT1 = HF XTAL
//  //* Min Vcc required varies with MCLK frequency - refer to datasheet *//
//
//  As coded with TACLK= HF XTAL and assuming HF XTAL = 8MHz, toggle rates are:
//  P1.1 = TACCR0 = 8MHz/(2*200) = 20kHz
//  P1.2 = TACCR1 = 8MHz/(2*1000) = 4kHz
//  P1.3 = TACCR2 = 8MHz/(2*10000) = 400Hz
//  P1.0 = overflow = 8MHz/(2*65536) = 61Hz
//
//               MSP430F22x4
//            -----------------
//        /|\|              XIN|-
//         | |                 | HF XTAL (3