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Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 703
UG585 (v1.11) September 27, 2016
Chapter 26: Reset System
26.2 Reset Sources
26.2.1 Power-on Reset (PS_POR_B)
The PS supports external power-on reset signals. The power-on reset is the master reset of the entire
chip. This signal resets every register in the device capable of being reset. While PS_POR_B is held
Low, all PS I/Os are held in 3-state.
The PS_POR_B reset pin is held Low until all PS power supplies are at their required voltage levels and
PS_CLK is active. It can be asynchronously asserted and is internally synchronized and filtered. The
filter prevents High-going glitches from entering the PS while the signal is intended to be held Low.
X-Ref Target - Figure 26-3
Figure 26-3: Power-On Reset Flow Diagram
Stable PS_CLK clock
Release PS_POR_B
Process Boot Image Header
BootROM starts to execute
System Resets
Software
SRST_B
Watchdog Timers
Security Reset
De-assert all Resets for
CPUs and peripherals
Sample Bootstrap Pins
PLL
BYPASS?
(BOOT_MODE)
RAM Memory Clear
De-assert DBGRESET
Apply eFUSE bits
Wait for PLLs to Lock
No
UG585_c26_03_121113
Yes
Stable Voltage
User Visible
User Visible
User Visible
User Code
User Config
Power-on
Reset
Sequence