I’m designing a bare bones TX2 system. It only has Ethernet and a debug serial port. I am strapping CHARGER_PRSNT# to ground for auto-start. I am specifically interested in the minimum connections necessary to get a TX2 to boot. I know that Table 88 of the design guide has suggested external connections, but don’t put much stock in it as I checked the Carrier Board schematic and not a single one of the recommended terminations were followed.
Also, I have strapped my Carrier Board for auto-start and measured the key signals as there is no timing diagram for the auto-start case. Interestingly, CARRIER_PWR_ON goes true 200 mS after Vin is applied and VIN_PWR_BAD# goes false (high) ~300 mS after power is applied. This is the opposite of Figure 3 in the DG.
question 1: What is the absolute minimum external parts count (assuming Vin is external) required to boot a TX2?
Question 2: Given that the Carrier Board de-asserts VIN_PWR_BAD 100 mS after CARRIER_PER_ON what is the proper sequence for this bare bones system?
TX2 scope captures.docx (87.1 KB)