I've been playing around with an idea for a little hand-held gaming device using a Nokia 5110 screen and an ATtiny85.
The ATtiny is programmed using my Genuino UNO as ISP.
I was wondering if it's possible/sensible to include a breakout connector on the attiny pins so I can just plug it in whenever I want to update the code, rather than having to remove it from the gaming device? I'm worried about how signals from the ISP would interfere with the other devices connected?
I used Fritzing for the very first time to create a diagram of what I'm thinking of so far (I've breadboarded parts of it with the UNO instead of the ATtiny, and I haven't actually tested sharing the clock & data pins with the 3 controllers yet! The real thing would have more buttons and LEDs!)