Toyota Inverter Clocked Serial Interface Protocol

[Viewtop1]

Hi All
Hope this is the correct place to ask this question.

In the Zombieverter Source, I see that a timer is setup to a pin that to provide the Clock signal for the Serial Interface.
and according to the wiki this is constant 500KHz.

I cannot find where the actual data transmission from the VCU to Inverter is actually Synced to this clock.

It appears the USART2 is not configured for Synchronous Master mode, but simply as a UART+ PWM Clock. Nor as a Slave mode that would accept a clock...( But slave SPI mode does not do Start and Stop bits...)
Am I missing something?

If just free running, could you then just use a UART + 50% PWM clock from any MCU?
Just something I am trying to get my small head around...

Any Insights appreciated...
Thanks

[Pete9008]

This thread might help https://openinverter.org/forum/viewtopic.php?t=205

[Viewtop1]

Hi Pete
Thanks, read that thread, but it does not answer my question about the free running Clock. So maybe I should have rather posted in VCU thread
Setting the USART to Synchronous mode does not deliver a constant 500Khz. It only clocks on data bits as per the datasheet.

[Pete9008]

The Toyota interface doesn't look like either true SPI or synchronous serial but in theory using an asynchronous UARTs should work fine for receiving data from the inverter. Sending data to the inverter is a little more questionable as it depends how the inverter sampling works and how it synchronises, afraid I don't know enough to comment further here though.

Edit - think the only way to find out for sure whether a continuous clock is needed and whether clock phasing matters is to try it!

Edit2 - I'm being stupid, it obviously needs a continuous clock as otherwise it wouldn't be active while receiving!