An unexpected recount

In the previous post, I briefly mentioned that I hadn't managed to upload code to the ATtiny using a Raspberry Pi. At that point, finishing the project was the focus, so I went with the first working solution, but the problem has been bugging me ever since, so here comes act two. The plan is to get the connection between the Raspberry Pi and the ATtiny working using some new hardware. Then we can get to know the inner workings of the ATtiny a little bit more. Level shifting I read somewhere that the Pi's 3.3V GPIO pins might not be enough for the ATtiny, which prefers 5V. To solve this, I ordered a few ICs known as the CD4504: ┌───┬──┬───┐ VCC ┤ • └──┘ ├ VDD A OUT ┤ ├ F OUT A IN ┤ ├ F IN B OUT ┤ ├ SELECT B IN ┤ CD4504 ├ E OUT C OUT ┤ ├ E IN C IN ┤ ├ D OUT VSS ┤ ├ D IN └──────────┘ It may not be the perfect choice for this purpose, but it might come in handy in other projects later. The point of the chip is that it replaces the voltage received on VCC with the one received on VDD. For…