Other Parts Discussed in Thread: TLV803
Hello community,
Our team is using the discrete power solution for the AM437x processor as described in slvuab1a.pdf on a custom board with AM437x processor. After struggling to understand why we cannot read the value of the pin gpio_0_22 (N20, mode 9, as described in the AM437x datashee) properly, we found that the same pin when configured in its default mode (7, gpio3_24, as described in the AM437x datasheet) works as it should. Also, by coincidence we found out that the issue with 0_22 is solved when we remove the TLV70215, and instead attach an external 1.5V supply. At first, this sounds like a timing issue, as the ENABLE pin of the TLV6208 is connected to the 1.5V, and furthermore the power good pin of the TLV6208 is connected to the TLV803, which should drive NRESET to high after a delay of 200ms. However, we still don't understand the real origin of this issue, since other pins are working properly even when not configured in their default mode. Furthermore, to our best understanding, the pin configuration as defined in the pinmux file is called in the board initialization function which is a part of the application code and thus it is very unlikely that there is a timing issue, as the program code is loaded onto the core after running the emulation file and the whole process is way above the specified 200ms.
While the issue could be solved just by changing the pinmux file, we would still like to know the real cause such that we can fix it before ordering a new batch of boards. We are happy for any hints that could help us find the origin of this issue.
Thank you in advance,
Liliane
