User manual

Table Of Contents
Zynq-7000 AP SoC Technical Reference Manual www.xilinx.com 185
UG585 (v1.11) September 27, 2016
Chapter 6: Boot and Configuration
ECC Management
The NAND controller can manage 1 bit of ECC in hardware. For more details on the ECC capabilities
of the controller, see Chapter 11, Static Memory Controller. The BootROM is aware of on-die ECC
devices and disables the controller ECC checking, allowing the NAND device to take care of ECC.
Memory Partitions
The BootROM treats NAND flash as one continuous partition. From a user perspective, this only
affects the Multiboot register. The Multiboot register value written is offset by the number of bad
blocks leading up to the target address. Consider the following example:
°
Image with two multiboot sections
°
Image is 1 MB in size
°
Block size is 128 KB
°
Second multiboot section starts at 512 KB
°
Bad blocks are located at 128 KB and 256 KB offsets
In this scenario, the image should be programmed as one partition, which results in the second
multiboot section being offset by 256 KB total (two blocks worth). When the Multiboot register is
written, it can be set to 512 KB offset and the BootROM takes care of calculating the new start
address based on where the bad blocks reside.
I/O Signal Timing
The BootROM uses the following NAND timing values in the smc.SET_CYCLES register:
t_rr = 2, t_ar = 2, t_clr = 1, t_wp = 3, t_rea = 2, t_wc = 5, t_rc = 5
6.3.6 NOR Boot
NOR boot has these features:
x8 asynchronous flash devices
Densities up to 256 Mb
Execute-in-place option
The BootROM does not try to perform any configuration detection of NOR flash devices. When NOR
is the selected boot device, the BootROM programs the MIO pins as shown in Table 6-13.
Note: The NOR interface is not available in 7z010 dual core and 7z007s single core CLG225 devices.