I have some project what requires all GPIO pins of attiny10 so I have to program RSTDISBL fuse. But only programmer I have is low voltage USBasp (with latest firmware supporting TPI interface).
The datasheet offers the way to re-program attiny10 by applying +12V to RST when RSTDISBL are programmed:
15.3.1. Enabling The following sequence enables the Tiny Programming Interface: • Apply 5V between VCC and GND • Depending on the method of reset to be used: – Either: wait tTOUT (see System and Reset Characteristics) and then set the RESET pin low. This will reset the device and enable the TPI physical layer. The RESET pin must then be kept low for the entire programming session – Or: if the RSTDISBL configuration bit has been programmed, apply 12V to the RESET pin. The RESET pin must be kept at 12V for the entire programming session
The USBAsp programmer doesn't supports 12V operation but I assume I could use simple inverting (because at normal operation it pulls logic low during programming and I need to pull it up to +12V) level shifter for this?
Should a circuit like this work? RST_OUT are RST pin from USBasup while RST_IN are RESET pin of ATtiny10.
Another question here is about the common ground. +5V are coming from Vusb via USBasp and +12V are coming from some sort of other PSU. Is it acceptable to combine grounds here? Or is is better to get +12V from PC PSU (same where Vusb comes from)?