Note that earlier versions of the AM57x SOM (PCM-057.A5 and earlier) populate C251 with a 1uF capacitor, which is connected between X_PWRON and ground. This capacitor will introduce further delay on the X_PWRON rise/fall time, potentially causing the board not to respond or boot as expected. The design was updated to populate C251 with a smaller 0.1uF capacitor, which results in an X_PWRON response similar to Figure 2. Consider this capacitor value when implementing this design with an older version of the SOM.