msp430x21x2_ta0_09.c

来自「msp430f21x2程序例程」· C语言 代码 · 共 25 行

//******************************************************************************
//  MSP430F21x2 Demo - Timer0_A3, Toggle P1.0-3, Cont. Mode ISR, HF XTAL ACLK
//
//  Description: Use Timer0_A3 CCRx units and overflow to generate four
//  independent timing intervals. For demonstration, TA0CCR0, TA0CCR1 and TA0CCR2
//  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 TA0CCRx
//  registers match the TA0R counter. Interrupts are also enabled with all
//  TA0CCRx units, software loads offset to next interval only - as long as the
//  interval offset is added to TA0CCRx, toggle rate is generated in hardware.
//  Timer0_A1 overflow ISR is used to toggle P1.0 with software. Proper use
//  of the TA0IV interrupt vector generator is demonstrated.
//  ACLK = MCLK = TA0CLK = LFXT1 = HF XTAL
//  //* Min Vcc required varies with MCLK frequency - refer to datasheet *//
//
//  As coded with TA0CLK= HF XTAL and assuming HF XTAL = 8MHz, toggle rates are:
//  P1.1 = TA0CCR0 = 8MHz/(2*200) = 20kHz
//  P1.2 = TA0CCR1 = 8MHz/(2*1000) = 4kHz
//  P1.3 = TA0CCR2 = 8MHz/(2*10000) = 400Hz
//  P1.0 = overflow = 8MHz/(2*65536) = 61Hz
//
//               MSP430F21x2
//            -----------------
//        /|\|              XIN|-
//         | |                 | HF XTAL (3