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Microsecond Bus or DSPI on ESP32

Posted: Mon Apr 25, 2022 7:59 pm
by gaston_fabbietti
Hi everyone. This is my first post but I have been a user of the forum for years and it has always been very helpful.
i am wanting to interface the ESP32 with an L9779 from ST Microelectronics for an automotive device.
The L9779 uses the MSC port (Microsecond communication or microsecond bus) which is very similar to SPI.
I wanted to know if it is possible to work with this type of communication and if someone has already done it before

L9779 datasheet: https://www.st.com/resource/en/datasheet/l9779wd.pdf

I appreciate any help

Thanks

Re: Microsecond Bus or DSPI on ESP32

Posted: Tue Apr 26, 2022 1:15 am
by ESP_Sprite
What a curious bus. Yes, at first glance I think this should be doable. You can use the GPIO matrix to net you a 2nd inverted MOSI /SCK output for the SPI bus, giving you a differential signal without external components. Current/voltage limiting on the differential pairs can likely be done using series resistors. The only thing that might be tricky is reading the (lower-speed) upstream data frames, as the ESP32 does not have a feature of reading input data at a fraction of the clock: you may simply need to read a bunch of bytes and parse them as one bit.