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Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 700
UG585 (v1.11) September 27, 2016
Chapter 26
Reset System
26.1 Introduction
The reset system includes resets generated by hardware, watchdog timers, the JTAG controller, and
software. Every module and system in Zynq-7000 AP SoC devices includes a reset that is driven by
the reset system. Hardware resets are driven by the power-on reset signal (PS_POR_B) and the system
reset signal (PS_SRST_B).
There are three watchdog timers in the PS that can generate resets. The JTAG controller can generate
a reset that only resets the debug portion of the PS and a system-level reset. Software can generate
individual sub-module resets or a system-level reset.
Resets are caused by many different sources and go to many different destinations. This chapter
identifies all of the resets and either explains their functionality or provides a pointer to another
chapter or another document.
26.1.1 Features
The key features of the reset system:
Collects resets from hardware, watchdog timers, the JTAG controller and software
Drives the reset of every module and subsystem
Is an integral part of the device security system
Executes a three-stage sequence: power-on, memory clear, and system enabling
26.1.2 Block Diagram
Figure 26-1 illustrates the logical dependencies of the main types of generated resets upon these
reset triggers. This block diagram is intended to highlight dependencies, and does not accurately
depict implementation detail or sequence timing.