i.MX8 Mini JTAG Interface

[shawnnageli]

Looking at the schematics for the 8MMINILPD4 base board design JTAG interface to the processor I am curious about the functionality and purpose of diodes D907 and D908.  Are these used to to control the nRST and keep the JTAG from overriding POR_B?  I have the snapshot from the schematic showing the diodes in question.

[Rita_Wang]

Hi,

So sorry for late reply. I have confirmed it for you. The power domain of POR_B is VSNVS, the power domian of Jtag IO is DCDC_3V3. External Jtag device output nRST signal to our system, its power domain is different our system. So D1905 and D1906 is for isolation of different power domain, in order to keep the current from flowing back.

Hope this can do help for you.

Have a nice day

Best Regards

Rita