ICSP

[2camjohn]

I need to set up a programming connector to program two PICS at once.

My question is: Can I have the data and CLK lines going to both PICS, but the MCLRs separate, so when I connect one MCLR it programmes one PIC, and when I connect the other MCLR it programmes the other?





Secondly:
I need to have my PIC16F675 wired up as below (notice GP2 and GP1 are connected together).

Will that work?


Thanks guys
John

 

[kentken]

I don't think it would work right, when the PIC isn't in programing state the pin wount pull up right (Internal resistances, Diodes, Etc).
Try manualy activate the data, clock pins (test mode in programer software), and see the voltages you get.
What this means is that one will cause problems for the other.

A bootloader type setup might work for your project.

Kent

 

[Jay.slovak]

Are you realy using 16F675? I think you ment 12F675. And why did you connect GP1 and GP2 ? Only GP0 and GP1 are needed for clock+data. I don't think bootloader will be a good choice, because 12F series are missing USART and all communication will have to be done in software. And don't forget to add an pull-up (4K7 - 20K) resistor to Mclr, to prevent weird operation. 8)

 

[Exo]

If the first pic tri-states its pins before you program the other i don't see any reason why it wouldn't work.

Of course then there is the problem of letting the other pic know it has to tristate its pins.