How to use Port C

Sid2286 · Joined: 12 Aug 2010 Posts: 119

Well,

I was working with MCP3208 with port B with a given example EX_AD12.C.
and it was working fine.
Now I tried with port C and the pins were replaced as follows:-

Pin B0-> Pin C0
Pin B1-> Pin C1
Pin B2-> Pin C2
and Pin B3-> Pin C3

I saw the datasheet of 18f452 wherein Pin C3 is said to be "RC3 can also be the synchronous serial clock for both SPI and I2C modes."

So does that mean C3 cannot be used for above mentioned circuit where the pins are replace???

Please reply.. Since the connections are made fine. but I'm not able to get any results.

Regards,
Sid

Sid2286 · Joined: 12 Aug 2010 Posts: 119

and please also update me on how to use that pin C3 for i/o as well.

temtronic · Posted: Tue Dec 21, 2010 6:57 am

Yes and no...

Yes, you can use it for any I/O providing you disabled any internal peripheral that uses those pins. IE, disable the SPI/I2C 'stuff' if you want to use the pins for your LCD.

No, you can't use those pins IF you need to use them for SPI/I2C or whatever peripheral is 'attached' internally.

Also be aware that some pins may only be an INPUT (ie: GP3 of the 12F683), or are an open collector and will need a pullup resistor to work 'normal'.

Chips with internal OSC allow the user to 'reuse' the OSC1,OSC2 pins for I/O ,it's all in the setup.

Same goes for the _MCLR pin.The option exists to 'reuse' it as an INPUT, providing you select that mode in the FUSES.

Sid2286 · Joined: 12 Aug 2010 Posts: 119

Ok so unless and until I'm not using spi or i2c on the same pins I can use them as i/o, right? How do I disable the internal peripherals in ccs?

Ttelmah · Joined: 11 Mar 2010 Posts: 19505

setup_spi(FALSE);

Best Wishes