A handy tool to have on the bench is a Flash chip programmer, and the ones based around the CH341A USB bus converter chip ... expands its capabilities. The software provides easy access to a ...

[Kimio Kosaka] wrote a dual-purpose TPI and ISP firmware for the ATmegaxxUn chips that are used as a USB-serial ... a DIY TPI programmer before, but it required a bespoke uploader software on ...