The following table lists the user case for Bypass Back Level Protection.
Table 1. Bypass Back Level Protection Use Case| Step |
SPI Bitstream |
Action |
Result |
Design Version |
Design Back Level Version |
Device Back Level Version |
|---|
| 1 |
Golden/Recovery |
Auto Programming |
Pass |
2 |
1 |
1 |
| 2 |
IAP/Update Bitstream |
Auto Update/IAP |
Pass |
3 |
2 |
2 |
| 3 |
IAP/Update Bitstream |
Auto Update/IAP |
Fail, Attempt Programming Recovery |
4 |
Not Enabled
|
2 |
The steps are described as follows:
- 1.The device programs with a bitstream version 2
and back level version 1. The current device back
level version is set to 1.
- 2.The device then updates with a bitstream version
3 and back level version 2.
The current device
back level version is set to 2.
- 3.The device attempts to update itself with a
bitstream version 4 and fails to update. In this case, the device
attempts to recover using a golden/recovery bitstream version 2. But
the recovery also fails as the current device back level protection
is set to version 2 and the golden/recovery bitstream version is
equal to the back level version. The Bypass Back Level
Protection must be enabled (see Figure 1) for Golden/Recovery bitstream to avoid
programming recovery failures because of back level protection.