CC2541 Button Switch Detection

pietro miotto

I need to perform a simple task but I can not find how to do it. I have a button attached to port P0.0, all I need to do is detect when it is pressed, high or low.

P0SEL = 0; // Configure Port 0 as GPIO
P1SEL = 0; // Configure Port 1 as GPIO
P2SEL = 0; // Configure Port 2 as GPIO

P0DIR = 0xFC; // Port 0 pins P0.0 and P0.1 as input (buttons),
// all others (P0.2-P0.7) as output
P1DIR = 0xFF; // All port 1 pins (P1.0-P1.7) as output
P2DIR = 0x1F; // All port 1 pins (P2.0-P2.4) as output

P0 = 0x03; // All pins on port 0 to low except for P0.0 and P0.1 (buttons)
P1 = 0; // All pins on port 1 to low
P2 = 0; // All pins on port 2 to low

After this, I don't know how to read the state of port P0.0

Thanks for your assistance

over 10 years ago

0 JXS over 10 years ago

TI__Guru** 105180 points

Hi Pietro,

Have you looked at the KeyFob reference project in the SDK? This has a good button press example.

Best wishes

0 pietro miotto over 10 years ago in reply to JXS

Intellectual 270 points

thanks for getting back.

Yes I have. Here's a better question, say I have a periodically method running and I want to read the state of a pin as in low or high?

0 Dhaval V over 10 years ago in reply to pietro miotto

Genius 4470 points

The P0 register returns value of that port GPIOs. So you can directly read P0 register.

For example to detect whether P0.0 is high or not you can do (P0 & 0x01).

Hope this helps.

0 pietro miotto over 10 years ago in reply to Dhaval V

Intellectual 270 points

Very helpful, thank you

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CC2541 Button Switch Detection