Problem with Ethernut-Board: Pin 3 on PortB

[Roman Walpuski]

Hi all!
I have a problem with pin 3 at PortB. Whenever i set pin 3 and pin 4 to high,
voltage on pin3 drops to ca 1 volts. when pin4 is not set to high, everything is fine.
 
The same occurs on 3 different Ethernut-Boards, so i dont think it is an hardware-fault.
 
The Board is a Ethernut 2.1 RevB, Nut/OS is Version  4.6.4
my Code:
 
#include <stdio.h>
#include <io.h>
 
void main()
{
   sbi(DDRB,0);
   sbi(DDRB,1);
   sbi(DDRB,2);
   sbi(DDRB,3);
   sbi(DDRB,4);
   sbi(DDRB,5);
   sbi(DDRB,6);
   sbi(DDRB,7);
 
   sbi(PORTB,3);
   sbi(PORTB,4);
 
   while(1)
   {
      int i = 0;
   }
}
with leds attached to the pins, every pin works fine, except pin3 which goes down when pin4 is high.
 
Has anybody noticed something like this before? What am i doing wrong?
 
 
Thanks in advance
 
Roman


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[Ole Reinhardt-2]

Hi!

> I have a problem with pin 3 at PortB. Whenever i set pin 3 and pin 4 to high,
> voltage on pin3 drops to ca 1 volts. when pin4 is not set to high, everything is fine.

This sounds quite strange. Can you give me some ascii art of your
external wiring?

Are these boards from egnite or are they self build?

Your code looks fine, there should'nt be any problem.

Regards,

Ole

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[Ethernut]

Hi Roman,

Roman Walpuski wrote:
> I have a problem with pin 3 at PortB. Whenever i set pin 3 and pin 4 to high,
> voltage on pin3 drops to ca 1 volts. when pin4 is not set to high, everything is fine.

Please have a look to

http://www.ethernut.de/en/hardware/enut2/ports.html

PB1, PB2 and PB3 are used by SPI. PB4 is the positive chip select of the
only on-board SPI slave, the serial Dataflash chip. Setting PB4 to high
will select this chip and enable its output connected to PB3.

You should avoid to use PB1-PB3 for GPIO. If you need to, you must keep
PB4 low.

If you don't need the Dataflash at all, you may cut the trace coming
from the Via near IC11 pin 1. R7, a pull-down, will keep pins 1 and 2
low and you can use PB4 for GPIO too (schematic page 2).

Harald


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