c - 如何使用msp430获取执行时间？

Question

我希望 C 代码的执行时间以毫秒为单位，我使用 msp430f16。

我们将不胜感激。

谢谢。

Answer 1

http://github.com/dwelch67/msp430_samples

示例显示使用计时器测量的时间段，对前后的计时器进行采样并减去差值，即为您的执行时间。

编辑:

此示例使用定时器和除数，而不是监视翻转标志读取定时器计数器寄存器并假设您计算的滴答数超过定时器的滴答数，从另一个减去一个来获得时间。调整除数以避免翻滚，并尝试获得您所追求的准确性。

    ;This version is written for naken430asm.
    ;http://www.mikekohn.net/micro/naken430asm_msp430_assembler.php
    ;naken430asm -o filename.hex filename.s
    ;mspdebug takes hex files as well as elfs.

WDTCTL equ 0x0120


CALBC1_1MHZ equ 0x10FF
CALDCO_1MHZ equ 0x10FE

DCOCTL  equ 0x56
BCSCTL1 equ 0x57
BCSCTL2 equ 0x58

TACTL   equ 0x0160
TAR     equ 0x0170
TACCR0  equ 0x0172
TACCTL0 equ 0x0162

P1OUT   equ 0x0021
P1DIR   equ 0x0022


    org 0xFC00

reset:
    mov #0x0280,r1

    mov #0x5A80,&WDTCTL ; 0x5A00|WDTHOLD

    ; use calibrated clock
    clr.b &DCOCTL
    mov.b &CALBC1_1MHZ,&BCSCTL1
    mov.b &CALDCO_1MHZ,&DCOCTL

    ; make p1.0 and p1.6 outputs
    bis.b #0x41,&P1DIR
    bic.b #0x41,&P1OUT
    bis.b #0x40,&P1OUT

    ; 1MHz is 1000000 clocks per second
    ; 1000000 = 0xF4240
    ; The timers are 16 bit
    ; Using a divide by 8 in BCSCTL2 gives
    ; 125000 (0x1E848) clocks in a second
    ; Using a divide by 8 in the timer gives
    ; 15625 (0x3D09) timer ticks per second.

    ; If both divisors are by 8, and we set
    ; TACCR0 to 0x3D08 and set for count up mode
    ; then, theory, we can measure seconds.

    bis.b #0x06,&BCSCTL2
    mov #0x02C4,&TACTL
    mov #0x3D08,&TACCR0
    mov #0x02D0,&TACTL
    ;mov #0x02D0,&TACTL ; use this instead to blink faster

loop:
    xor.b #0x41,&P1OUT
loop0:
    bit.w #0x0001,&TACCTL0
    jz loop0
    bic.w #0x0001,&TACCTL0

    jmp loop


hang:
    jmp hang

    org 0xFFE0
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw hang
    dw reset

此示例使用定时器来测量传输串行 (rs232) 字符的时间段，如上所述调整除数以确保您不会计算超过一个定时器周期(定时器可以翻转，这很好 0xF000例如到 0x3000，不是问题，0xF000，大约一次到 0xF100，这是一个问题)。如果可能严重超过除法，这样你就绝对不会翻车，请缩小除数，直到获得最佳精度。

是的，您可以使用中断来处理翻转，但这会弄乱您要测量的东西，您不想这样做(除非中断的开销或您用来监视定时器翻转的任何机制(你不需要为此中断)你的测量是可以接受的)。

#define WDTCTL     (*((volatile unsigned short *)0x0120))

#define CALBC1_1MHZ (*((volatile unsigned char *)0x10FF))
#define CALDCO_1MHZ (*((volatile unsigned char *)0x10FE))
#define CALBC1_8MHZ (*((volatile unsigned char *)0x10FD))
#define CALDCO_8MHZ (*((volatile unsigned char *)0x10FC))
#define CALBC1_12MHZ (*((volatile unsigned char *)0x10FB))
#define CALDCO_12MHZ (*((volatile unsigned char *)0x10FA))
#define CALBC1_16MHZ (*((volatile unsigned char *)0x10F9))
#define CALDCO_16MHZ (*((volatile unsigned char *)0x10F8))

#define DCOCTL  (*((volatile unsigned char *)0x56))
#define BCSCTL1 (*((volatile unsigned char *)0x57))
#define BCSCTL2 (*((volatile unsigned char *)0x58))

#define TACTL   (*((volatile unsigned short *)0x0160))
#define TAR     (*((volatile unsigned short *)0x0170))
#define TACCR0  (*((volatile unsigned short *)0x0172))
#define TACCTL0 (*((volatile unsigned short *)0x0162))


#define P1IN  (*((volatile unsigned char *)0x0020))
#define P1OUT (*((volatile unsigned char *)0x0021))
#define P1DIR (*((volatile unsigned char *)0x0022))

// 16MHz clock
// The timer is 16 bit
// set to divide by 1
// 16,000,000 / 155200 = 138.88889
#define TACCR0_VALUE 138

//-------------------------------------------------------------------
void uart_putc ( unsigned short c )
{
    unsigned short sa;
    unsigned short sb;
    unsigned short then,now;

    sa=c<<1;
    sa|=1<<9;
    sb=10;
    then=TAR;
    while(sb--)
    {
        if(sa&1) P1OUT|=1; else P1OUT&=(~1);
        sa>>=1;
        while(1)
        {
            now=TAR-then;
            if(now>TACCR0_VALUE) break;
        }
        then+=TACCR0_VALUE;
    }
}
//-------------------------------------------------------------------
void hexstring ( unsigned short d, unsigned short cr )
{
    //unsigned short ra;
    unsigned short rb;
    unsigned short rc;

    rb=16;
    while(1)
    {
        rb-=4;
        rc=(d>>rb)&0xF;
        if(rc>9) rc+=0x37; else rc+=0x30;
        uart_putc(rc);
        if(rb==0) break;
    }
    if(cr)
    {
        uart_putc(0x0D);
        uart_putc(0x0A);
    }
    else
    {
        uart_putc(0x20);
    }
}
//-------------------------------------------------------------------
void notmain ( void )
{
    unsigned short /*sa,*/sb;
    //unsigned short start;
    unsigned short then; //,now;
    unsigned short bitin;
    //unsigned short log[32];

    WDTCTL = 0x5A80;

    // use calibrated clock
    DCOCTL = 0x00;
    BCSCTL1 = CALBC1_16MHZ;
    DCOCTL = CALDCO_16MHZ;

    // make p1.0 an output
    P1DIR |= 0x01;
    P1OUT |= 0x01;

    P1DIR &= ~0x02;


    BCSCTL2&=~0x06;
    TACTL = 0x0204;
    TACTL = 0x0220;

    hexstring(0x1234,1);
    hexstring(0x5678,1);

    while(1)
    {
        //sa=0;
        bitin=0;
        while(1) if((P1IN&2)==0) break;
        then=TAR;
        while(1)
        {
            if((TAR-then)>=(TACCR0_VALUE>>1)) break;
        }
        if(P1IN&2)
        {
            bitin>>=1;
            bitin|=1<<9;
        }
        else
        {
            bitin>>=1;
        }
        then+=(TACCR0_VALUE>>1);
            for(sb=0;sb<9;sb++)
        {
            while(1)
            {
                if((TAR-then)>=TACCR0_VALUE) break;
            }
            if(P1IN&2)
            {
                bitin>>=1;
                bitin|=1<<9;
            }
            else
            {
                bitin>>=1;
            }
            then+=TACCR0_VALUE;
        }
        hexstring(bitin,0);  hexstring(bitin>>1,1);
    }
}
//-------------------------------------------------------------------
//-------------------------------------------------------------------

llvm 的 msp430 后端是真正的实验性的，阅读:坏掉了，不要过度依赖它，而不仅仅是玩它，gcc 编译器不是微不足道的，但构建起来也不会太痛苦。 naken430asm 汇编器非常易于使用，该处理器的 asm 也非常简单，良好的架构...