St's L6470 stepper motor drivers

Hello.

I'm new to the forum, so I thought I'd introduce myself with a little sideproject i'm working on.

While browsing to see the latest in stepper-motor drivers, one cought my eye. Its ST's L6470. I found it interesting because it relies on SPI communication rather than conventional EN, DIR and STEP signals. Thus potentially saving 3 IOs per stepper motor. This means a smaller microcontroller could be utilized compared to the more expensive sam3x, lpc1769 or other $10+ chips. It can also run in a sort of hybrid mode which means that the STEP signal is still suplied by the microcontroller, but the EN and DIR signals are transferred via SPI. If you have 6 stepper drivers, then you already saved 12 IOs in hybrid mode or 18 IOs if you were to controll it solely via SPI.

I looked at the latest marlin bugfix 2.0 to see if there was any mention of these drivers and to my suprise there was. I've made a little board based on a STM32F103 microcontroller. L6470 prototype board. Its nowhere near finished btw.


I'm trying to compile the project with L6470 drivers, but I can't seem to get it to compile. I've opened a bugreport but I've gotten no responses.
Are these drivers still viable or maybe not?