2.9.1.7.11 SD Card/e.MMC Memory Boot Configuration (Fourth Word)
This word is the fourth word used to add an external SD card/e.MMC Flash memory in the boot sequence. Its content is used when the Dual Boot feature is enabled in the MEM_CFGx[2] word. It allows to inform the ROM Code the file name of the secondary bootstrap in the external FAT formatted SD card/e.MMC Flash memory.
| Name: | MEM_CFGx[3] |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| DUALBOOT_CFG[31:24] | |||||||||
| Access | |||||||||
| Reset | |||||||||
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| DUALBOOT_CFG[23:16] | |||||||||
| Access | |||||||||
| Reset | |||||||||
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| DUALBOOT_CFG[15:8] | |||||||||
| Access | |||||||||
| Reset | |||||||||
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| DUALBOOT_CFG[7:0] | |||||||||
| Access | |||||||||
| Reset | |||||||||
Bits 31:0 – DUALBOOT_CFG[31:0] Bootstrap Filename Suffix
- W = DUALBOOT_CFG[31:24]
- X = DUALBOOT_CFG[23:16]
- Y = DUALBOOT_CFG[15:8]
- Z = DUALBOOT_CFG[7:0]
The secondary bootstrap is found on FAT formatted SD/e.MMC as a file named “bootWXYZ.bin” (or “.cip”) in the root filesystem directory (e.g. 0x313233334 for boot1234.bin, 0x5F326E64 for boot_2nd.bin).