TAHOE 8622 User Guide
REV: 01
07/27/2017 PAGE 25 OF 37
8.4
Selecting Boot Device
Registered BOOT_CSR in the CPLD Selects Boot Device
The boot device could be selected by writing the appropriate values into BDSL_2 and
BDSL_3
BOOT_CSR –
Boot Control and Status
7
6
5
4
3
2
1
0
CN_FAILSF res res res BDSL_3 BDSL_2 res res
Table 2, Boot Device Register
bit 7
CN_FAILSF – CPU Failsafe
Upon reset, it is set to 1, but if the CPU fails to boot it is set to 0.
bits 6:4
Reserved
bits 3:2
BDSL [3:2] – Boot Device Select
Upon power up, SPI NOR is selected as default device.
The software can change these bits and cause a re-boot by writing a 1 into
the RE_BOOT bit.
These bits are not changed by a hardware reset.
BDSL_ [3:2] Boot Device
11
eMMC
10
SPI Flash
01
reserved
00
SD Card
Table 3, Boot Device Bits
