I've returned to a project that was initially the subject of this post but it meandered a bit off topic.
The design has 6x ATtiny84 slaves and an ATmega328 master on SPI. The design will now be all SMD, meaning programming in-circuit is needed. To use ISP to program them, I had this setup in mind: ...which will switch the SPI clock.
I didn't like the above as it just seems there has to be a less clunky way. Could I achieve the same switching the Reset? I'm thinking here of leaving the RST line open circuit, with a jumper at each microcontroller to complete the circuit to that specific reset pin. SPI would be connected to all microcontrollers, but only one of them would get the reset pulse to program with a jumper in place.
Is that a neater/better/simpler or even functional solution?
Thanks for your help in sanity checking, Geoff