MAX32672 - Alternate Function Configuration

[leoreyesth]

The MXC_GPIO_RevA_SetAF() function needs to be updated to match the data from the User Guide.

I think that there is a typo on the procedure to select an alternate function. Step 3 it should reference table 6-5. If this is the case the procedure should be the following: 1 - Set the transition acording to table 6-6 2 - Optional: Configure the electrical characteristics of the pin. 3 - Set the GPIO Mode acording to table 6-5

Is this procedure correct?

This steps require to modify three different registers. Is there a specific order to follow or the order doesn't matter?

[BobbyCounts]

Hi @leoreyesth , the documentation is incorrect. Table 6-5 has incorrect settings that have been revised in the latest revision of the ME21 User Guide as well as procedure steps 1-3. However, the revised user guide will not be available until it is published.

Please see this corrected AF selection table:

As for the order to set the EN bits, I recommend setting EN0 first. This will put the GPIO into I/O mode and prevent glitches from occurring when setting the other EN bits. Not setting EN0 first may cause the GPIO to enter unintended AFs, causing potential glitches.

I recommend this procedure for setting AF EN bits:

1. Set EN0 to transition to I/O mode
2. Configure other EN bits as required for the desired AF. Here you can also configure electrical characteristics.
3. Clear EN0 to transition from I/O mode to AF mode

MXC_GPIO_RevA_SetAF() should be modified to use this register write order to ensure glitch-less transition from AF to AF.