ColdFire/68K Microcontrollers and Processors中的主题 IN PUT 5282 no 0 detecting

IN PUT 5282 no 0 detecting

Lucho — Mon, 30 Apr 2007 21:02:18 GMT

Hi, my problems is that I can't detect a 0 in the register for IN PUT data, I only detec 1's This is my simple code:

int main()
{
    int i;
    MCF5282_GPIO_PBCDPAR = 0x00;
    MCF5282_GPIO_DDRB = 0xFF;
    MCF5282_GPIO_DDRC = 0x00;
    MCF5282_GPIO_PORTB = 0x00;
    MCF5282_GPIO_PORTCP = MCF5282_GPIO_PORTCP & 0x01;

    while(1)
    {
         i = MCF5282_GPIO_PORTCP;

         if(i = 0x00){
         MCF5282_GPIO_PORTB = 0x55;
         }

       if(i = 0x01){
       MCF5282_GPIO_PORTB = 0xAA;
       }
    }// Idle
return 0;
}

This program is very simple but I can't do that the register MCF5282_GPIO_PORTCP detect a cero, it only detect logic 1's

Re: IN PUT 5282 no 0 detecting

mccPaul — Mon, 30 Apr 2007 21:33:23 GMT

PortC is input so this:

MCF5282_GPIO_PORTCP = MCF5282_GPIO_PORTCP & 0x01;

is not doing anything.

You code only tests for PortC set to 0x00 or to 0x01 - maybe there is some other input to PortC, try and replace:

if(i = 0x01)

with

else

Now you can see if there is any input detected at all.

Sorry I can't try out your code on one of my boards because I always have an external address bus and these ports are not available. If you find that you still have no result, can you try a different pair of ports?

Paul.

Re: IN PUT 5282 no 0 detecting

Lucho — Mon, 30 Apr 2007 21:37:18 GMT

Ok, May be I will practice with other Ports because I try with simples program with the PORTCP

Re: IN PUT 5282 no 0 detecting

stzari — Wed, 02 May 2007 19:26:12 GMT

Hi,

testing for a value might also make more sense than assigning one.
Your code should read:
Code:

if (i == 0x00) {

HTH
Stamatis