Hi,
I need to use a couple of PIC digital outputs for SPI chip select pins and a third for enabling comms in a particular direction on my MAX485. Whats not clear to me is what the output type are in these PICs; 18f87jk22, i.e. open drain, push-pull etc. my thoughts are, if this is Open drain I guess I will need to provide a pull up at the input to the devices Im interfacing with, however if the PIC output was push pull then it would drive to either logic without the need for a pull-up/down resistor. On a previous job I used a similar pin to chip select and hadnt used a pull up and received no issues, but this could be a fluke I guess.
One of the pins are as follows, the rest are identical:
Pin Name: RH1
Pin Type: I/O
Buffer Type: ST (Schmitt trigger input with CMOS levels)
Description: Digital IO
I need to use a couple of PIC digital outputs for SPI chip select pins and a third for enabling comms in a particular direction on my MAX485. Whats not clear to me is what the output type are in these PICs; 18f87jk22, i.e. open drain, push-pull etc. my thoughts are, if this is Open drain I guess I will need to provide a pull up at the input to the devices Im interfacing with, however if the PIC output was push pull then it would drive to either logic without the need for a pull-up/down resistor. On a previous job I used a similar pin to chip select and hadnt used a pull up and received no issues, but this could be a fluke I guess.
One of the pins are as follows, the rest are identical:
Pin Name: RH1
Pin Type: I/O
Buffer Type: ST (Schmitt trigger input with CMOS levels)
Description: Digital IO