1 AMCC Ebony Board 2 3 Last Update: September 12, 2002 4======================================================================= 5 6This file contains some handy info regarding U-Boot and the AMCC 7Ebony evalutation board. See the README.ppc440 for additional 8information. 9 10 11SWITCH SETTINGS & JUMPERS 12========================== 13 14Here's what I've been using successfully. If you feel inclined to 15change things ... please read the docs! 16 17DIPSW U46 U80 18------------------------ 19SW 1 off on 20SW 2 on on 21SW 3 on on 22SW 4 off on 23SW 5 on off 24SW 6 on on 25SW 7 on off 26SW 8 on off 27 28J41: strapped 29J42: open 30 31All others are factory default. 32 33 34I2C iprobe 35===================== 36 37The i2c utilities have been tested on both Rev B. and Rev C. and 38look good. The CONFIG_SYS_I2C_NOPROBES macro is defined to prevent 39probing the CDCV850 clock controller at address 0x69 (since reading 40it causes the i2c implementation to misbehave. The output of 41iprobe should look like this (assuming you are only using a single 42SO-DIMM: 43 44=> iprobe 45Valid chip addresses: 50 53 54 46Excluded chip addresses: 69 47 48 49GETTING OUT OF I2C TROUBLE 50=========================== 51 52If you're like me ... you may have screwed up your bootstrap serial 53eeprom ... or worse, your SPD eeprom when experimenting with the 54i2c commands. If so, here are some ideas on how to get out of 55trouble: 56 57Serial bootstrap eeprom corruption: 58----------------------------------- 59Power down the board and set the following straps: 60 61J41 - open 62J42 - strapped 63 64This will select the default sys0 and sys1 settings (the serial 65eeproms are not used). Then power up the board and fix the serial 66eeprom using the imm command. Here are the values I currently 67use: 68 69=> imd 50 0 10 700000: bf a2 04 01 ae 94 11 00 00 00 00 00 00 00 00 00 ................ 71 72=> imd 54 0 10 730000: 8f b3 24 01 4d 14 11 00 00 00 00 00 00 00 00 00 ..$.M........... 74 75Once you have the eeproms set correctly change the 76J41/J42 straps as you desire. 77 78SPD eeprom corruption: 79------------------------ 80I've corrupted the SPD eeprom several times ... perhaps too much coffee 81and not enough presence of mind ;-). By default, the ebony code uses 82the SPD to initialize the DDR SDRAM control registers. So if the SPD 83eeprom is corrupted, U-Boot will never get into ram. Here's how I got 84out of this situation: 85 860. First, _before_ playing with the i2c utilities, do an iprobe, then 87use imd to capture the various device contents to a file. Some day 88you may be glad you did this ... trust me :-). Otherwise try the 89following: 90 911. In the include/configs/EBONY.h file find the line that defines 92the CONFIG_SPD_EEPROM macro and undefine it. E.g: 93 94#undef CONFIG_SPD_EEPROM 95 96This will make the code use default SDRAM control register 97settings without using the SPD eeprom. 98 992. Rebuild U-Boot 100 1013. Load the new U-Boot image and reboot ebony. 102 1034. Repair the SPD eeprom using the imm command. Here's the eeprom 104contents that work with the default SO-DIMM that comes with the 105ebony board (micron 8VDDT164AG-265A1). Note: these are probably 106_not_ the factory settings ... but they work. 107 108=> imd 53 0 10 80 1090000: 80 08 07 0c 0a 01 40 00 04 75 75 00 80 08 00 01 ......@..uu..... 1100010: 0e 04 0c 01 02 20 00 a0 75 00 00 50 3c 50 2d 20 ..... ..u..P<P- 1110020: 90 90 50 50 00 00 00 00 00 41 4b 34 32 75 00 00 ..PP.....AK42u.. 1120030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 9c ................ 1130040: 2c 00 00 00 00 00 00 00 08 38 56 44 44 54 31 36 ,........8VDDT16 1140050: 36 34 41 47 2d 32 36 35 41 31 20 01 00 01 2c 63 64AG-265A1 ...,c 1150060: 22 25 ab 00 00 00 00 00 00 00 00 00 00 00 00 00 "%.............. 1160070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 117 118 119PCI DOUBLE-ENUMERATION WOES 120=========================== 121 122If you're not using PCI-X cards and are simply using 32-bit and/or 12333 MHz cards via extenders and the like, you may notice that the 124initial pci scan reports various devices twice ... and configuration 125does not succeed (one or more devices are enumerated twice). To correct 126this we replaced the 2K ohm resistor on the IDSEL line(s) with a 12722 ohm resistor and the problem went away. This change hasn't broken 128anything yet -- use at your own risk. 129 130We never tested anything other than 33 MHz/32-bit cards. If you have 131the chance to do this, please let me know how things turn out :-) 132 133 134Regards, 135--Scott 136<smcnutt@artesyncp.com> 137