PS-only Reset - PS-only Reset - 2026.1 English - UG1137

Zynq UltraScale+ MPSoC Software Developer Guide (UG1137)

Document ID
UG1137
Release Date
2026-07-22
Version
2026.1 English

The PS-only reset re-boots the PS while that PL remains active. You can trigger the PS-only reset by hardware error signal(s) or a software register write. If the PS-only reset is due to an error signal, then the error can be indicated to the PL also, so that the PL can prepare for the PR restart.

The PS-only reset sequence can be implemented as follows:

  • [ErrorLogic] Error interrupt is asserted whose action requires PS-only reset. This request is sent to PMU as an interrupt.
  • [PMU-FW] Set PMU Error (=>PS-only reset) to indicate to PL.

See the PS Only Reset section in the “Reset System” chapter of the Zynq UltraScale+ Device Technical Reference Manual (UG1085) describes the PS-only reset sequence.

Note: PS-only reset is not supported in qspi24 mode on systems with a flash size that is greater than 16 MB.

PS-only Restart on WDT Timeout Error

Enable all the flags listed in the Wiki Zynq UltraScale+ MPSoC Restart solution, compile the necessary components, and boot the system. After waiting for the 60-second, if the WDT is not kicked, it will get expired and triggers a PS-only restart to recover the system.