Completely agree with the HW solutions here. One of the 74x04 inverters will work, depending on the specifics of your setup. https://www.ti.com/lit/ds/symlink/sn74ls04.pdf?ts=1622518492304&ref_url=https%253A%252F%252Fen.wikipedia.org%252F
On Tue, 1 Jun 2021 at 13:10, Konrad Rosenbaum <[email protected]> wrote: > Hi, > > On 01/06/2021 19:59, John Klimek wrote: > > I'm using avrdude (v6.3-20171130) on my Raspberry Pi, but I need the > > RST pin to be inverted because I'm using an NPN transistor to protect > > the RPi from my Arduino's 5V power. > > A completely dumb idea: add another NPN transistor to invert the pin > again - then there is no need to mess about with the pin and syntax. > > You could also use a logic level change circuit, like the common BSS138 > based circuits you get relatively cheap on eBay or Amazon. > > You also need to protect the other lines (MISO, MOSI, ...). > > Alternatively you could supply the Arduino from a 3.3V supply via the > 6pin programming port - the AVR chip on it can usually work with this > without much trouble (even though the datasheet says it needs 5V at 16MHz). > > > Konrad > > >
