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Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 156
UG585 (v1.11) September 27, 2016
Chapter 6: Boot and Configuration
The user code can force the device into a secure lockdown, if desired, by writing to the devcfg.CTRL
[FORCE_RST] bit. A POR reset is required to start up the system from this and all secure lockdowns.
FSBL Image Fallback and Multiboot
If the FSBL detects an error or wants to use a different FSBL image, then it writes the boot image
address to the devcfg.MULTIBOOT_ADDR [MULTIBOOT_ADDR] field and performs a software system
reset. This is briefly described in section 6.3.11 MultiBoot. Also refer to UG821
, Zynq-7000 All
Programmable SoC Software Developers Guide for information on how to use both fallback and
multiboot.
6.1.7 PL Boot Process
The PL boot process includes start-up, initialization, configuration, and enable.
Start-up (power-up the PL voltage).
Initialization (using PS software or INIT/PROGRAM control pins).
Configuration (through PS PCAP, JTAG, or PL ICAP).
Enable PS-PL Interface (using PS software).
These steps and their subcomponents are illustrated in Figure 6-1, page 150.
6.1.8 PL Configuration Paths
The PL can be configured and reconfigured by PS software in secure or non-secure mode. The PCAP
path is the most commonly deployed method as it does not require that the PL be pre-programmed
with a bitstream. The PL can also be configured by the TAP controller on the JTAG chain in
non-secure mode. Multiplexing of the datapath is done in the PL configuration module using the
devc.CTRL [PCAP_MODE] and [PCAP_PR] bits. Also refer to section 6.5 Reference Section.
JTAG debug using TAP Controller (common for development):
°
Non-secure
°
Initialize and configure the PL through the TAP controller.
PS PCAP path (common for deployment):
°
Secure or non-secure.
°
Initialize and configure the PL through the device configuration interface (DevC).
ICAP path (not a common option):
°
Secure or non-secure.
°
Reconfiguration only by logic instantiated in the PL.