MSP432E401Y: For MSP432E401 ,does there have a function like __delay_cycles in MSP430?

Jacky Hsu

Part Number: MSP432E401Y

As We know there is a function __delay_cycles at MSP430 series

This function can keep a delay by MCU clocks.

#include <msp430g2231.h>
void main (void)
{
    WDTCTL = WDTPW + WDTHOLD ;


    for(;;)
    {
    P1DIR |= BIT0+BIT6;
    P1OUT ^= BIT0;
    __delay_cycles(1);
        P1OUT ^=BIT6;
        __delay_cycles(2);
    }
    }
}

But I can find these function in DriverLib for MSP432E401

Is there a way or function to let MCU delay one clock? I need one delay about 40ns (1/25MHz) if OSC frequency is 25MHz

over 3 years ago

0 Bruce McKenney over 3 years ago

Guru 101755 points

I've used __delay_cycles() in the MSP432E series. I think it's a compiler intrinsic, so you probably won't find the source.

I wouldn't count on getting a 1-clock delay out of it, since it uses a 3-clock loop + loading the count. For that you should probably use something like

> asm volatile (" nop "); // Pause for 1 clock

0 Jacky Hsu over 3 years ago in reply to Bruce McKenney

Prodigy 100 points

Bruce McKenney said:
asm volatile (" nop ");

It doesn't work ,I still can't get a pulse with 40ns width....Could you provide more detail how to initial it ?

thanks

0 Bruce McKenney over 3 years ago in reply to Jacky Hsu

Guru 101755 points

That statement just inserts a NOP (no-operation) instruction into the code; the NOP does nothing for 1 CPU clock time, which provides a 1-clock delay.

Creating a one-CPU-clock wide pulse is a different thing, since you have to consider the CPU clocks (I'm guessing >20) it takes to switch the pin state twice; i.e. you won't succeed with this by directly changing the pins, even with no delay. (You can't really do this in the MSP430 either.)

I suspect the PWM generator can do this, by setting CMPB = CMPA+1 [Ref TRM (SLAU723A) Sec 21.3.4], but I haven't tried it. Examples for using the PWM generator can be found in Resource Explorer:

https://dev.ti.com/tirex/explore/node?node=AHuMXn0JNAfhu2ng-3xZzg__J4.hfJy__LATEST

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MSP432E401Y: For MSP432E401 ,does there have a function like __delay_cycles in MSP430?