NVIDIA Carrier Board Design - Reason for separate suspend clock M/E key


We are designing our custom carrier board for the Jetson NX, and are using the NVIDIA carrier board as a reference. We are wondering about the motivation for not connecting the M-key SUSCLK to the Jetson NX CLK_32K_OUT, but to a separate 32KHz oscillator. While the E-key does have its SUSCLK directly connected to the CLK_32K_OUT of the Jetson NX.

What is the reason for this design? Could both SUSCLKs be connected to the Jetson NX?

Thanks in advance!



That is for CL of M-key and E-key devices. If devices plug in at same time, the CL might be higher than the limit of system 32khz, so add an oscillator for M-key.