6 Configuration Mode Introduction
6.5 MSPI
UG290-2.5.2E
68(98)
there is no limit placed on the number of RECONFIG_N events.
Using MULTI BOOT with Failsafe Golden Images
To support remote ‘infield’ bitstream updates, Multiboot can include a
failsafe Golden Image. We recommend this Golden (fallback) Image is
always stored as the last bitstream in external Flash. In the example below,
if Working Images 0x0 or 0x1 are corrupted, we can pulse RECONFIG_N
low to load the next bitstream, using the SPI Flash Address in the current
image header as a jump address. This Jump Address could either by the
start address of the next Working Image in Flash, or the start address of the
Golden (fallback) Image in Flash.
Additionally, if all Working images are erased, then the FPGA will
continue reading Flash Addresses until the Golden Image is reached.
In the unlikely event all the Flash images are corrupted, the SPI Flash
will need to be reprogrammed via the JTAG/SSPI interface.
Figure 6-44 Example of Bitstream Image Distribution in Flash Memory
For example,
Working Image 0x0
resides at the default 0x0000
power-on address.
Working Image 0x0
includes a SPI Flash Jump Address to
Working
Image 0x1
.
Working Image 0x1
includes a SPI Flash Jump Address to
Golden
Image 0x2
.
Following Power-On,
Working Image 0x0
will automatically be loaded
from 0x0000.
If the 1
st
Working Image 0x0
load fails and the FPGA supports more
than one configuration load attempt, the FPGA will then try to load next
Working Image 0x1
.
If the 2
nd
Working Image 0x1
load fails and the FPGA supports more
than two configuration load attempts, the FPGA will then try to load
Golden