By default, all full and partial PL programming images are compressed. Versal uses a new compression algorithm that is a different approach than the prior architectures. Versal PDI compression reduces the configuration time in most cases.
Reduced configuration time and decreased configuration storage size requirements
is observed when compression is used for the following interfaces for QSPI, OSPI, SD,
eMMC, JTAG, and SelectMAP:
- Less than 2.56 GB/s (in the slowest speed grade)
- 3.2 GB/s (in medium and fast speed grades)
Note: The configuration
time is affected when Versal programmable device
image (
.pdi) is compressed and if the interface
exceeds 2.56 GB/s (slow speed grades) or 3.2 GB/s (medium and fast speed
grades).The maximum bandwidth of the Versal PMC
configuration frame unit (CFU) is 5.12 GB/s (for slow speed grade) or 6.4 GB/s (for
medium and fast speed grades). When an interface exceeds either 2.56 GB/s or 3.2 GB/s,
the bandwidth will be throttled.
- Use uncompressed image
- For the high-speed interfaces that requires shortest programming time when images are delivered from DDR memory or through PCIe.
- Use compression
- For the high-speed interfaces if the primary goal is minimizing storage space.
To disable compression, apply this property prior to running
write_device_image:
set_property BITSTREAM.GENERAL.COMPRESS TRUE [current_design]Note: Bandwidth is
calculated based on the uncompressed data size. For example, if a full xcvc1902 PDI
(medium speed grade) contains approximately 90 MB of CFI data then the time required
to load this data is 90 MB/3.2 GB/s = 27.9 ms.