Port Pin Control

[rayhall]

I know this is very basic if you know the way to control the pins on ports. I am stuck.

DDRD = 0xFF;  // Set the pins as outputs

PORTD = 0xFF; // Turns on the pullups

How do you set PD0 low. This does not work PORTD_PDO = 0x00;

Ray.

[rayhall]

I have it now working. I am not sure if there is a better way to control the pins. This works.

PUCR |= 0x08;

//set pull up on Port D

  DDRD_DDRD0=0x01;  // set direction as output

  for(;;) {

	PORTD |= PORTD_PD0;
	Delay_ms(2000);
	PORTD = ~PORTD_PD0;
	_FEED_COP(); /* feeds the dog */

  } /* loop forever */

It is weird how you must use PORT_PD0  and 0x01 is ignored.

Ray.

[Martin35804]

Hi,

to make the proper port off again try to and it with the neg. value of the port.

PORTD &= ~(PORTD_PD0);

[rayhall]

Martin,

I get nothing when using.

PORTD |= PORTD_PD0;

asm nop;

PORTD &= ~PORTD_PD0;

This works...

PORTD = 0x01;

asm nop;

PORTD = 0x00;

So does this...

PORTD |= (1<<0);

asm nop;

PORTD &= ~(1<<0);

They work correctly as long as I do not use my delay method. See reply to Zhang.

Ray.

[ZhangJennie]

hi Ray,

it is not  "must", I just do a quick test if  PORT_PD0 can function normal. you can modify the code as your requirement.

Have a great day,
Zhang Jun

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[rayhall]

Zhang,

it is not  "must", I just do a quick test if  PORT_PD0 can function normal. you can modify the code as your requirement.

It is not that I want to modify your example. It is that this did not work.

  PORTD_PD0=0x00;  //set output pin as low

  asm nop;

  PORTD_PD0=0x01;  //set output pin as high

I would have expected your example to work as that is what I have used with other MCU. I wish someone could explain what possible reason you cannot set the bits for the pins.

Ray.

[ZhangJennie · Accepted solution]

Hi Ray,

maybe I don't understand.

I just tested the code on my side, I can see portd bit0 at memory 0x0005 got toggled with

  PORTD_PD0=0x00;  //set output pin as low

  asm nop;

  PORTD_PD0=0x01;  //set output pin as high

see attached video.

Have a great day,
Zhang Jun

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[rayhall]

Zhang,

If I use this code I get this pattern on my oscilloscope. http://www.turbofast.com.au/tfbin/TEK0000.JPG which is correct.

PORTD |= (1<<0);

asm nop;

PORTD &= ~(1<<0);

If I use this code I get this pattern which is wrong. http://www.turbofast.com.au/tfbin/TEK0001.JPG

PORTD |= (1<<0);

Delay_us(1);

PORTD &= ~(1<<0);

For some reason my delay method is causing problems. This is its code.

#define F_BUS 50  // 50mHz

#define  LOOP_US    ((F_BUS*1000000/6000000)+1)

void Delay_us(unsigned short ms){

    unsigned short j, k;

    for(j=0;j<ms;j++){

        for(k=0;k<LOOP_US;k++){

        }

    }

}

Ray.

[rayhall]

Sorry....My delay method is working correctly. The code should have another delay like this.

PORTD |= (1<<0);

Delay_us(1);

PORTD &= ~(1<<0);

Delay_us(1);

Sorry for all the confusion. Thank you all,  for your help.

Ray.

[ZhangJennie]

Hi Ray,

please refer this code:

PUCR = 0x08;

//set pull up

  DDRD_DDRD0=0x01;  // set direction as output

  PORTD_PD0=0x00;  //set output pin as low

  asm nop;

  PORTD_PD0=0x01;  //set output pin as high

can this help?

Have a great day,
Zhang Jun

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[rayhall]

Zhang,

I have found that you cannot set the pullup like this. PUCR = 0x08; It causes debug break point errors.

You have to use PUCR |= 0x08;

To set Port C and D pullups you cannot use PURC = 0x0C;

You have to do this...

PUCR |= 0x04;

PUCR |= 0x08;

I still cannot set the pins high or low, and need help with this. Why is such a basic thing so hard..

Ray.

[rayhall]

Zhang,

I get a ILLEGAL_BP when I use the PURC = 0x08; and the pin does not change.

This is my test code,

PUCR = 0x08;

//set pull up

  DDRD_DDRD0=0x01;  // set direction as output

  for(;;) {

	PORTD_PD0=0x00;  //set output pin as low
	Delay_ms(2000);
	PORTD_PD0=0x01;  //set output pin as high

;  

_FEED_COP(); /* feeds the dog */

  } /* loop forever */

This below does work...Why ?

   DDRD = 0x01;

  PORTD = 0x01;

  for(;;) {

     Delay_ms(2000);

     PORTD_PD0 = ~PORTD_PD0;

    _FEED_COP(); /* feeds the dog */

  } /* loop forever */

Ray.

[iggi]

Ray, what MCU do you use?

[rayhall]

iggi,

I am using the 144 pin S12XEP100

Ray.

[ZhangJennie]

please post here your project. thanks!

Have a great day,
Zhang Jun

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[rayhall]

Zhang,

Here is the project,

http://www.turbofast.com.au/tfbin/LCDtest.zip

Ray.