PIC 18F452 problem

dijuka · Joined: 26 Apr 2004 Posts: 2

I am using PIC 18F452 with CCS v3.179. I haven't been able to get PIN_A4 and PIN_A6 to high. What am I doing wrong?

fpgeh · Joined: 07 Sep 2003 Posts: 19 Location: Vancouver, BC

Pin A4 is an open drain pin. This means it can only drive low. To get the pin high, you will need a pullup reistor to Vcc.

As for pin A6, I'm not sure what the porblem could be. The datasheet does say that on a Power-On Reset pins A4 and A6 are configured as inputs, the rest of port A as outputs.

fpgeh · Joined: 07 Sep 2003 Posts: 19 Location: Vancouver, BC

Sorry, to correct. On Power-On reset, Pins A4 and A6 are configured as digital inputs, the rest as analog inputs.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

dijuka · Joined: 26 Apr 2004 Posts: 2

Thank you for helping out.

Birdasaur · Joined: 07 Oct 2003 Posts: 29

After changing the Fuse statement appropriately, how would we access PIN_A6?

add a manual define to your file like

#define PIN_A6 31750

??

I ask because it isn't really available anywhere in the header file that I see and wouldn't compile otherwise.

Mark · Joined: 07 Sep 2003 Posts: 2838 Location: Atlanta, GA

That would be one way. You can always manipulate the bits in the registers also.