SPINet

Some more pictures of the SPINet module prototype. Fischer SIL 1 G 20 / 10045917 really seem to be somewhat cheaper than the MillMax equivalents.

The contacts should have been a lot shorter, allowing a shielding can to be fitted to the top, and soldered on the bottom side around the exposed strips.

The test board also includes PoE taps, which will be investigated later.

SPINet has had some traces moved around and now incorporates two new I/O mapping flavors:

- simple Quadrature Decoder: PHA+PHB only (utilizes the primary UART pins, however the ACT and LNK LEDs can be disconnected and a secondary UART option is routed to these pins). That's what was possible on a 2-layer PCB in the given area.

- full Quadrature Decoder with rotation signal: PHA+PHB+IDX: (utilizes UART pins, LNK LED pin), maintains ACT pins

all options do not touch I2C and SPI I/Os.

Spot the differences ;-)

ps. via-in-pad is usually not a good idea. However we gave the PCBs a shot and found the small via ID in conjunction with stop mask on the bottom layer (which tents/plugs the vias halfway through) keeps solder wicking under control. Back-to-back caps also seem to work without a concerning amount of tombstoning. Not good practice in general but ok-ish if proven to work under real conditions.