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- 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).
- This is an example how to program an example MAC address 01:23:45:67:89:ab
- into the eFuses. Assure that the programming voltage is available and then
- execute:
- => fuse prog -y 1 9 01 23 45 67 89 ab
- After programming a MAC address, consider locking the MAC fuses. This is
- done by programming the MAC_ADDR_LOCK fuse, which is bit 4 of word 0 in
- bank 1:
- => fuse prog -y 1 0 10
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