Shared Projects by nsayer

Note that the left side does not have a 2x6 header - it’s two identical 1x6 headers.

Populate the right footprint with a shrouded 2x3 male connector and populate one of the columns on the left with a 1x6 male connector on the bottom to connect to a breadboard. The other 1x6 header is available for probe tips.

Adapts a USBTiny (or some other ISP programmer) for TPI by connecting MOSI and MISO together (with resistors) to make a combined DATA signal. R1 should (probably) be 0Ω and R2 1 kΩ, but those are guesses. The idea is to connect the DATA pin directly to the programmer’s input, but connect the output with some extra impedance so the chip can override it.

This is a convenient way to break out the SPI device on a Raspberry Pi. The 2x3 header has the same pinout as the AVR ISP, with the !RESET line replaced with !CS. In fact, you probably could use this to perform AVR ISP programming at 3.3v.

The SOT23-3 is an AP2331 that protects the Pi’s 3.3v bus from short circuit and hot-plug transients. The two caps are 0.1µF.

This little board will adapt a Bus Pirate v4 for programming SPI flash chips. The 6 pin pinout is the same as the AVR ISP pinout, with !CS substituted for !RESET. If you add that connector to your board to facilitate flash programming in situ, then all you have to do is do whatever is necessary to keep the SPI bus quiescent (usually just holding the controller in RESET will work), then program away.