Interfacing a groups of pic controllers to a common personal computer

can anyone plz help me out by telling how to interface a group of PIC controllers to a common personal computer so that the entire result of the output of the PIC'S is stored in the form of a data sheet in computer...i wuld like to use PIC ICF887 or 877,,also gve me suggestions of using a differnt PIC chip...

REGARds
manoj

try looking 18f4550 as it got USB interface which could be easy to interface to PC. and other PIC's(mostly low end) to 18f4550. so result would be transmitted to 18F and then to PC.In PC you would need to develop some GUI so that it can accept data from 18F and would process it asa datasheet

you can communicate with PC through serial port. (use USB to serial converter cable)

Well, even if you have figured out a PIC that has a serial interface, your next challenge will be how to let multiple PICs talk to the same serial port, as a PC usually have only one serial port or limited to USBs if you're converting them to serial.
In this case you need to build an intermidiate circuit with a multiplexer to send the query command to the PICs and get the results and tag it one at a time. should be fairly easy to implement.
The intermediate circuit should be another PIC (with 2xUART) and a multiplexer IC. then you implement a program on your PC to talk only to the intermediate PIC.

ausrasul said:

Well, even if you have figured out a PIC that has a serial interface, your next challenge will be how to let multiple PICs talk to the same serial port, as a PC usually have only one serial port or limited to USBs if you're converting them to serial.
In this case you need to build an intermidiate circuit with a multiplexer to send the query command to the PICs and get the results and tag it one at a time. should be fairly easy to implement.
The intermediate circuit should be another PIC (with 2xUART) and a multiplexer IC. then you implement a program on your PC to talk only to the intermediate PIC.

Click to expand...

No need to do any of this...

Normally there are 3-4 usb ports in 1 system that means with the help of USB-to-Serial converter cables you can have 3-4 serial ports. If you need even more you can use a USB Hub device to expand one USB port into 4 more and so on. You can litterally conect 10-12 or even more PICs to ur PC directly ...Its simple.

I'd suggest things are getting a bit complex here.
I'd put that complexity into software rather than all those ports.

Make all the pics talk to each other so they can arbitrate the external communication between themselves.
You can use rs232 between the pics and usb or rs232 or anything else to the PC using a single port.

If you want to keep it simple (depending on what all the pics are doing) most pics have rs232 and any that need extra ones
can use a simulated port on 2 i/o lines. (Choose a good C compiler and its easy)
Depending on how clever you want to be you could use a star type topography with a pic capable of multiple interrupt levels
at the centre doing the comms to the PC.

Or keep it simple and do a ring or train network.
Much depends on what the system is doing and how critical each node is.
But there is lots of room for fun in such a design.

salmanliaquat said:

No need to do any of this...

Normally there are 3-4 usb ports in 1 system that means with the help of USB-to-Serial converter cables you can have 3-4 serial ports. If you need even more you can use a USB Hub device to expand one USB port into 4 more and so on. You can litterally conect 10-12 or even more PICs to ur PC directly ...Its simple.

Click to expand...

That leaves dependency on the controlling PC, which is not good if he want to switch in the future to an embedded system with only one RS232.
Also imagine the mess with the cascading hubs. not a good habit.
I agree more with 123Jack.

But again I agree with you if we just want a quick and dirty approach, that is simple and takes no time to implement.