A4.2 Voltage domains

The Cortex®-A55 core supports a VCPU voltage domain and a VSYS voltage domain.

The following figure shows the VCPU and VSYS voltage domains in each Cortex-A55 core and in the DSU. The example shows a configuration with four Cortex-A55 cores.

Figure A4-1 Cortex-A55 voltage domains
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Asynchronous bridge logic exists between the voltage domains. The Cortex-A55 core logic and core clock domain of the asynchronous bridge are in the VCPU voltage domain. The DSU clock domain of the asynchronous bridge is in the VSYS voltage domain.


You can tie VCPU and VSYS to the same supply if one of the following conditions is met:

  • The core is configured to run synchronously with the DSU sharing the same clock.
  • The core is not required to support DVFS.
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