We are designing a circuit with Aurix TC387. The micro controller is powered from 5V ( both VEXT and VFLEX).
We want to connect an ETAS XETK S20.1-B to the micro controller's DAP port for calibration. We saw that the DAP/ JTAG pins belongs to the VEXT domain and therefore 5V in our design. However, ETAS confirmed that the XETK S20.1-B supports only 3.3V DAP. Is there any simple solution without changing the microcontroller power supply to 3.3V?
Can we mitigate this by simply pulling-up the TCK, DAP1/TMS and DAP2 /TDI lines to 3.3V on our board? We are worried that, as there is no way to define the logic levels (TTL/ CMOS) for the TCK and TMS the micro controller will not treat 3.3V at these pins as a HIGH. OR do we need a level shifter?
Will a level shifter be mandatory in such applications? If a level shifter is the only solution, what type( single direction/ bi-direction) is needed for the DAP0, DA1 and DAP 2 pins? can you suggest any specific level-shifters ?
Can anyone please help? Thanks.
