AR# 65463

描述

When choosing a flash device to incorporate with Zynq UltraScale+ MPSoC devices, it is important to consider the following logistical criteria:

• Is the device supported for the Xilinx tools?
• Will the device work with the Zynq device BootROM?
• Is the device supported with software like U-Boot and Linux?

In addition, there are design considerations which include:

• How many pins are required for a configuration method?
• How much flash memory is required?
• How fast can the Zynq device be configured?
• How difficult is it to manage the flash device?

Based on the logistical criteria, there are four categories of flash devices:

Xilinx Tested and Supported Flash Devices

These devices meet the logistical criteria listed above.
These devices receive regression testing with Xilinx tools and their use is fully supported by Xilinx Technical Support.

Known to Work Flash Devices

These devices are not explicitly supported in the Xilinx tools, but have been known to work with Zynq UltraScale+ MPSoC devices.
Many of these devices are programmed using U-Boot as an alternate programming method, but source changes to U-Boot might have to be made by users in order to configure that specific device.

Unverified Flash Devices

These devices have not been tested in any way by Xilinx with Zynq UltraScale+ MPSoC devices.
There are NO known issues (but possible limitations) for these devices.
The user will be responsible for validating the flash on Zynq UltraScale+ MPSoC, making necessary changes to U-Boot and configuring the device.

Incompatible Flash Devices

These devices will not work on Zynq UltraScale+ MPSoC.

Note: Xilinx Technical Support will not be able to provide assistance with designs using "Known to Work" or "Unverified" flash devices.

Xilinx can only provide assistance for the devices listed as 'Xilinx Tested and Supported'.

解决方案

QSPI

Benefits of QSPI:

• High performance - QSPI is the fastest configuration solution.
• Low Pin count - QSPI has the lowest pin count of the configuration solution options besides SD.
• Easy management - QSPI can be accessed as linear memory in Zynq devices. In addition, NO bad blocks management is required.
• XIP - QSPI is the only mode that supports execute-in-place

Downsides of QSPI:

• Low memory density

Vendors

Configuration and Specifications

There are two distinct boot modes relative to QSPI:

• QSPI24: 24-bit addressing
• QSPI32: 32-bit addressing

NOTE:  Flash Devices larger than 16MB (128Mb) are only tested booting in QSPI32.

The QSPI boot image search limit are listed below.

NOTE(*): In case of Dual Stack Memory, Zynq UltraScale+ MPSoC only boots from the "lower" QSPI (Same as "Single Memory").

Xilinx Supported Devices

NAND

Benefits of NAND:

• High Memory density - NAND is an inexpensive solution for large density devices.

Downsides of NAND:

• Lower device performance - Maximum bandwidth is less than QSPI.
• High pin count - NAND devices require more pins than QSPI.
• Difficult Management - NAND devices are hard to manage. Bad blocks are a regular concern which require design decisions on how bad blocks will be managed for a particular system setup.

Vendors

Configuration and Specifications

Xilinx Supported Devices

SD

Benefits of SD:

• High density - SD has densities comparable to NAND.
• Easy Management - Device is generally managed as a file system. Bad blocks do not need to be managed in the user design.

Downsides of SD:

• Slow performance - SD is slower than QSPI
• Mechanical considerations - SD cards require a connector.

Configuration and Specifications

Consult (Xilinx Answer 66779) for the list of SD cards currently tested on Zynq UltraScale+ MPSoC. 

Xilinx Supported Devices

Any compliant card. See the SD/SDIO Controller Chapter of (UG1085).

eMMC

Benefits of eMMC:

• High density - eMMC has densities comparable to NAND.
• Easy Management - Device is generally managed as a file system. Bad blocks do not need to be managed in the user design.

Downsides of eMMC:

• Slow performance - eMMC is slower than QSPI

Configuration and Specifications

Xilinx Supported Devices:

NOTE (*): (UG908) reports the "Device Alias" as the JEDEC version and density of the flash (i.e. "jedec4.51-16gb").

There is no need to specify the "Manufacturer" in the tools.

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