stolzie
New Member
Hi,
I have an issue which I am not sure how I can get around and I need some help/adivse on some possible solutions that could be implemented.
I currently have an 8 bit bus that is a direct connection to a Port on a PIC18FXXXX that does not have programmable internal pullups available on the port.
What I need to do on the port is to be able to turn on pullups when the port is set for input and turn off pullups on the port when they are set to output.
I was thinking of using a bussed resistor network connected to VCC via a FET, and turning the FET on when set to input via a spare I/O pin. But I thought when the port is set to outputs, and the pins are toggled to certain states I would get a connection between certain port pins. So all pins would be in the on state?
If anyone can provide any useful tips or tricks that would be handy. I have been looking around at various other methods using mutliple fets and single resistors, but this option maybe the only way to go.
Thanks
Stolzie
I have an issue which I am not sure how I can get around and I need some help/adivse on some possible solutions that could be implemented.
I currently have an 8 bit bus that is a direct connection to a Port on a PIC18FXXXX that does not have programmable internal pullups available on the port.
What I need to do on the port is to be able to turn on pullups when the port is set for input and turn off pullups on the port when they are set to output.
I was thinking of using a bussed resistor network connected to VCC via a FET, and turning the FET on when set to input via a spare I/O pin. But I thought when the port is set to outputs, and the pins are toggled to certain states I would get a connection between certain port pins. So all pins would be in the on state?
If anyone can provide any useful tips or tricks that would be handy. I have been looking around at various other methods using mutliple fets and single resistors, but this option maybe the only way to go.
Thanks
Stolzie