SPI emulation with the RTBOX 1

General
1

Dear PLECS support,

we have implemented SPI communication on the RTBox using deterministic communication and always setting the expected slave answers previous to the falling edge of the master.

So the RT Box will always be the SPI slave, whereas the DUT will always be the SPI master.

Now we have faced the issue, that the RTBox in idle state (inactive chip select) seems to pull the MISO line down to GND so that the overall SPI communication is no longer possible with other SPI slaves.

Is our observation correct and the RTBox does indeed pull the MISO line to 0 in idle state? This would stop us from integrating the RTBox in our HIL test environment as an SPI slave.

Kind regards

Sebastian

2

By hardware design, the digital output lines of the RT Box do not have a high-impedance state, they are always in high or low state.

If you need a high impedance state that would have to be realized by external logic.