11.4.4 BFM Integrity Check
The Boot ROM can optionally perform an integrity check of the Boot Flash Memory (BFM). If BROM_EN_BFMCHK= 1, the Boot ROM calculates a CRC over the selected portion of the current BFM and compares the calculated value to the expected value in a CRC table (see section 2.2.2.1). If the CRC values do not match, the Boot ROM enters interactive mode. The BFM_CHK_TABLEPTR word specifies the location of the CRC table. Typically, the CRC table is stored in BFM. The default setting is BROM_EN_BFMCHK = 0.
When the CRC check fails for any reason (Incorrect CRC table, ECC error or CRC mismatch), the STATUS_ERR_BFMCRC is placed on the Boot communication channel for use by a debugger and interactive mode is called.
| Description | Header | Start Address(1) | Size in bytes(2) | Expected value(3) |
|---|---|---|---|---|
| Field | HDR | ADDR | SIZE | REFVAL |
| Offset | 0x0 | 0x4 | 0x8 | 0xC |
| Value | 0x43524349 | 0x00000000 | 0x100 | 0xAABBCCDD |
- The start address must be a multiple of 4 (Only ADDR[31:2] are used).
- The size must be a multiple of 4 (Only SIZE[31:2] are used).
- The expected value is the computed CRC32 value of the memory target.