Use the PIC 16f877 or 877A instead of shift registers.

[tsanders]

I would like to use the PIC16F877 or 877A in place of a 74hc595 for shift outputs and 74hc597 for inputs. I am trying to build an interface to the GE Fanuc PLC 90-30 backplane for trouble shooting. I have a module that uses the shift registers to communicate or transmit and receive inputs and outputs. I have traced the circuit out and made a schematic on the unit. But my main question is can this be done, substitute the PIC for the shift registers. I have seen lots of posts for using the shift registers, but none to use the PIC as the shift registers. Also, I have seen a module that used a PIC for this interface before, I do not recall the part number of the PIC, other than it was a 40 pin Dip. I do not have to use the 16F877, it is just the one I currently have on had, I could purchase a different unit if there is on that would do this better. Any input would be greatly appreciated.

[mister_e]

So we just need to add i/o? any 40 PINs pic will work. The software is the 'harder' part.

[tsanders]

Yes, I want to use the PIC as the I/O, the code is what I am worried about. I have been doing tons of reading on this and I am just not sure were to start. Do I use the shiftin/out, SPI, etc...I have the circut, with out the pic, only the shift registers and timing circuits breadborded and connected to the PLC backplane, it works and can view the input/output, It is an 8 bit input and 8 bit output on one card. I am useing an Agilent MSO6104A, mixed signal scope with 16 pin logic analizer built in. I can see timing and can show post the jpg of it if needed as well as the schematic in autocad, if that would help in the programming. I am just stuck and need some direction. I didn't want to have to bother the form with all this. But I guess I will have too.

[mister_e]

post what you have. The schematic have to be in JPG, png, Pdf, bmp.

If you can't convert it, use PrimoPDF. It act as a virtual printer. Easy to use and it's free.
http://www.primopdf.com/

[tsanders]

Let me know if there are any questions. I hope I can answer them...Ha Ha.