GPIO initialization/testing

[nad]

Posted on December 22, 2010 at 23:02

hello, 

I just started with the STM8S-discovery .

can you tell me how I boot the pine 0,1,2 port B as input.

and how I'm doing the test on the value entered.

if (?????)

{

    instruction 1....

} 

[brazov22]

Posted on December 23, 2010 at 11:50

i.e. for PORTC pin 0:

#define BUTTON_PORT (GPIOC)

#define BUTTON_PIN     (GPIO_PIN_0)

/* -------------------------------------------------------------*/

/* Check button status */

    if ((GPIO_ReadInputData(BUTTON_PORT) & BUTTON_PIN) == (u8)0x00)

    {

      /* Button is pressed */

      .....

      .....

    }

by default all ports are configured as input floating. If you want you can configure them as input pull up at the beginning before doing the check on pin port status:

 /* Initialize I/O in Input Mode with pull up and no interrupt*/

  GPIO_Init(BUTTON_PORT, BUTTON_PIN, GPIO_MODE_IN_PU_NO_IT);

I suggest you to configure it as input pull up so when button is not presd pin0 is high, when you press button pin0 is low.

brazov2

[nad]

Posted on December 29, 2010 at 23:05

sorry, I made a mistake with the pines. 

it works now 

thank you