Re: [ECOS] Problem reading buttons on AT91sam7s-ek

["Rasmus Stougaard" <stou.nospam@gmail.com>]

On 10/1/07, Andrew Lunn <andrew@lunn.ch> wrote:
> On Mon, Oct 01, 2007 at 02:27:32PM +0200, Rasmus Stougaard wrote:
> > Hi
> >
> > I am trying to read the state of the buttons on a AT91sam7s-ek
> > evaluation kit from atmel.
> >
> > I figure that something like:
> >
> >     cyg_uint32 value;
> >     HAL_ARM_AT91_GPIO_CFG_DIRECTION(AT91_GPIO_PA20, AT91_PIN_IN);
> >     HAL_ARM_AT91_GPIO_CFG_PULLUP(AT91_GPIO_PA20, AT91_PIN_PULLUP_ENABLE);
> >     HAL_ARM_AT91_GPIO_GET(AT91_GPIO_PA20, value);
> >     trace(" AT91_GPIO_PA20 %d\n", value);
> >
> > Should configure the pin for input and print the current state of the
> > of the pin.
>
> In general that looks O.K. Have you tried the other 3 switches?
>
> One idea i have. Is the clock to the GPIO device enabled? Check bit
> AT91_PMC_PCER_PIOA in AT91_PMC_PCER. Without a clock you can do
> output. But to do input you need the clock enabled.
>
>   Andrew
>
>

Hi Andrew

Thanks a lot, that solved it :-)

Here is my code for later reference (probably to myself)

int get_pin_state(int gpio_pin)
{
  int value;
  // Enable the clock to the GPIO (enable input sampling)
  HAL_WRITE_UINT32(AT91_PMC + AT91_PMC_PCER, AT91_PMC_PCER_PIOA);

  HAL_ARM_AT91_GPIO_CFG_DIRECTION(gpio_pin, AT91_PIN_IN);
  HAL_ARM_AT91_GPIO_GET(gpio_pin, value);

  return value;
}

Cheers
Rasmus

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