| 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 |