4.7.1 Processor’s Primary Clock
There are three external crystals attached to the J721E processor to provide the SoC’s Primary clocks
WKUP_LFOSC (32 KHz), WKUP_OSC0 (19.2 MHz) and OSC1 (22.5792 MHz) as shown in
.
Figure 4-9. J721E SoC Primary Clock
The WKUP_OSC0 is required by the processor. Both WKUP_LFOSC and OSC1 are optional clocks (not
required for J721E processing). The WKUP_LFOSC can be sourced either on the on-board crystal or from the
PMIC. The OSC1 can be sourced from either the on-board crystal or from clock generator (CDCEL937) on the
Common Processor board.
J721E EVM Hardware Architecture
40
Jacinto7 J721E/DRA829/TDA4VM Evaluation Module (EVM)
SPRUIS4D – MAY 2020 – REVISED MARCH 2022
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