mirror of
https://github.com/smaeul/u-boot.git
synced 2025-10-31 12:08:19 +00:00
29 lines
1.2 KiB
Plaintext
29 lines
1.2 KiB
Plaintext
U-Boot for Freescale i.MX5x
|
|
|
|
This file contains information for the port of U-Boot to the Freescale
|
|
i.MX5x SoCs.
|
|
|
|
1. CONFIGURATION OPTIONS/SETTINGS
|
|
---------------------------------
|
|
|
|
1.1 CONFIG_MX51_PLL_ERRATA: Workaround for i.MX51 PLL errata.
|
|
This option should be enabled by all boards using the i.MX51 silicon
|
|
version up until (including) 3.0 running at 800MHz.
|
|
The PLL's in the i.MX51 processor can go out of lock due to a metastable
|
|
condition in an analog flip-flop when used at high frequencies.
|
|
This workaround implements an undocumented feature in the PLL (dither
|
|
mode), which causes the effect of this failure to be much lower (in terms
|
|
of frequency deviation), avoiding system failure, or at least decreasing
|
|
the likelihood of system failure.
|
|
|
|
1.2 CONFIG_SYS_MAIN_PWR_ON: Trigger MAIN_PWR_ON upon startup.
|
|
This option should be enabled for boards having a SYS_ON_OFF_CTL signal
|
|
connected to GPIO1[23] and triggering the MAIN_PWR_ON signal like in the
|
|
reference designs.
|
|
|
|
2. CONVENTIONS FOR FUSE ASSIGNMENTS
|
|
-----------------------------------
|
|
|
|
2.1 MAC Address: It is stored in the words 9 to 14 of fuse bank 1, using the
|
|
natural MAC byte order (i.e. MSB first).
|