But why why why an stm32. A mega 256 will do the job too for a 2cv including sequential injection and ignition. Stm32 is onla a big pain in the ass.

I did ignition on a mega328 and with a second board with the lpg injection too. Never failed on me in 9 years. I'm thinking to do a simimilar board 2x2 sequential running on an Atmega 1284 and my own software. I have the schematc ready so far.

Faster clock speed, and expandable memory. Trying to future proof a little.

This is on my own board, and does not have an MCU plug into it. The firmware supports STM32, but not so sure about the config of the F411. I will need to edit the FW to support my pinout and my selection for SPI mosi, miso etc.

I also need to add some chips via hot air soldering.

I wanted a really small board as well. Idea is to bolt it on to the points box, in a simular way to a 123.

First thing is to do is see if it works at all.

Production is complete, and I'm waiting for FedEx to pick it up from China
Should be here by the end of next week

Edit
Subject to Customs of course

Ok, so .... If you have 2 black wires, and one of them has a white line running down it. Which would you say was positive, and which negative?

If i have faster clock speed i have to repair it....

I've lost the key to wind it up