I have four ATtiny2313 chips on one board sharing an eight-bit bus on their B ports. They also have their /RESET pins bussed together. The ISP signals are on the PortB pins.
How can I (without resorting to bus isolation chips or jumpers) add ISP headers to the board and program all four of them?
I'm trying to use the Atmel USB programmer, which uses MISO/MOSI and SCK, and AVR Studio 4.
Either four separate headers or one daisychain would be fine.
Incidentally, all four of them have exactly the same program in them, but I fear that the MISO drivers would fight with each other if I just connected the programmer up and went at it.
Can it be done?
PS - At the moment I program them in another board with only one installed, and then plug it into a socket on the target, but if I want to use surface-mounting that's impractical (yeah, there are SMT sockets, but they're $$$!) S.