Lpc2000

Hello,

  Some weird things happen when using PORT 1.

Firstly, make sure the debug and trace functions are disabled.

	regVal = PINSEL2;
	regVal &= ~((1 << 2) | (1 << 3));
	PINSEL2 = regVal;

Next, set the pins used as outputs to become outputs, and drive their
outputs high.

	regVal = (1 << 31) | (1 << 26) | (1 << 24);
	IODIR1 = regVal;
	IOPIN1 = regVal;

Constantly read the pin values and display.

        port1.26 is always flickering (i.e. on/off) when read.
        the output does not change, it remains driven high, just the
        readback from IOPIN1 shows this.

Further, a circuit to detect switch closures uses 8 bits of port 0 and
8 bits of port 1. The inputs to port 1 read as expected, but the
inputs to port 1 are always 'high'. Can this be explained?

Dave

--- In lpc2000@yahoogroups.com, "Dave" <dgsomerton@w...> wrote:
> Hello,
> 
>   Some weird things happen when using PORT 1.
> 
> Firstly, make sure the debug and trace functions are disabled.
> 
> 	regVal = PINSEL2;
> 	regVal &= ~((1 << 2) | (1 << 3));
> 	PINSEL2 = regVal;
> 
> Next, set the pins used as outputs to become outputs, and drive their
> outputs high.
> 
> 	regVal = (1 << 31) | (1 << 26) | (1 << 24);
> 	IODIR1 = regVal;
> 	IOPIN1 = regVal;
> 
> Constantly read the pin values and display.
> 
>         port1.26 is always flickering (i.e. on/off) when read.
>         the output does not change, it remains driven high, just the
>         readback from IOPIN1 shows this.
> 
> Further, a circuit to detect switch closures uses 8 bits of port 0 and
> 8 bits of port 1. The inputs to port 1 read as expected, but the
> inputs to port 1 are always 'high'. Can this be explained?
> 
> Dave

Typo:

> 8 bits of port 1. The inputs to port 1 read as expected, but the
> inputs to port 1 are always 'high'. Can this be explained?

 should be

> 8 bits of port 1. The inputs to port 0 read as expected, but the
> inputs to port 1 are always 'high'. Can this be explained?

Dave