Rb0 Int

[richb]

I've had a look around the forum but can't seem to find anything of any help.

I have a 10k resistor from RB0 to Vcc as a pull up and also connected my chip. The idea is that when my chip goes low, an ISR is fired (INTF).

The issue I am facing is my chip brings the line from (high -> low) can see this on the scope, but the ISR is only fired when the line goes back to high again. My chip (max3100) keeps the signal low until its registers are cleared.

My setup code is:-

	INTEDG	= 1;
	INTE	= 1;
	INTF	= 0;

The interrupt fires fine when i remove the low signal from the chip.

Any idea what I'm doing wrong guys?

Rich

 

[Pommie]

Try INTEDG=0;

Mike.

 

[richb]

was the first thing i tried, it didn't work initially

just tried it again after your post, it works

this is what you get for coding at 4 in the morning :S

thanks mate
Rich

 

[gramo]

You have to read port B and and set INTF = 0 after the interrupt occurs I think, theres more info in the datasheet.

By read, I mean using any read command

Temp_Byte = PORTB

 

[Pommie]

He is using RB0 int - not portb change and so there is no need to read portb.

Mike.