The S08JM is an S08 8-bit microcontroller subfamily.

I had big dreams of making an Arduino killer using this part, but now that dirt-cheap 48 MHz ARM Cortex-M0+ parts have arrived, that time has largely past.

This is still a really cool device. If you want a USB-capable, versatile, inexpensive, general-purpose 8-bit microcontroller, and are sold on the S08 architecture, the S08JM is a great choice. You have to be able and willing to deal with LQFP packages, however. It’s a bit disappointing that these chips aren’t available in more “approachable” packages. The Microchip PIC really wins in this regard. There are several PIC18 and PIC24 variants with built-in USB that come in DIP packages.

It wasn’t until Freescale introduced the S08JS subfamily in a friendlier-for-prototyping SOIC package that I jumped onto the USB bandwagon. I built a JS16 USB board that has for some time been my connection to all things microcontroller. Since the S08JM has a similar memory map and an identical USB interface, it should be trivial to get my USB code working on an S08JM – if I could make a board. (Actually, dipmicro now sell an LQFP 44 0.8mm pitch breakout board that would be perfect for this.)

The S08JM is really two sub-subfamilies:

JM8 and JM16

JM32 and JM60