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Timestamp:
03/20/01 04:22:49 (12 years ago)
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mds
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documentation updates on eeproms

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  • lm-sensors/trunk/doc/chips/eeprom

    r717 r1040  
    88    Prefix `eeprom' 
    99    Addresses scanned: I2C 0x50 - 0x57 (inclusive) 
    10     Datasheet: Publicly available from Intel 
     10    Datasheets: Publicly available from Atmel (www.atmel.com), 
     11                Fairchild (www.fairchildsemi.com), and 
     12                Microchip (www.microchip.com) 
     13 
     14        Chip    Size (bits)     Address 
     15        24C01    1K             0x50 (shadows at 0x51 - 0x57) 
     16        24C01A   1K             0x50 - 0x57 (Typical device on DIMMs) 
     17        24C02    2K             0x50 - 0x57 
     18        24C04    4K             0x50, 0x52, 0x54, 0x56 
     19                                (additional data at 0x51, 0x53, 0x55, 0x57) 
     20        24C08    8K             0x50, 0x54 (additional data at 0x51, 0x52, 
     21                                0x53, 0x55, 0x56, 0x57) 
     22        24C16   16K             0x50 (additional data at 0x51 - 0x57) 
     23 
    1124 
    1225Author: Frodo Looijaard <frodol@dds.nl> and Philip Edelbrock 
    … …  
    3851 
    3952This is a simple EEPROM module meant to enable reading the first 128 bytes 
    40 of an EEPROM (on a SDRAM DIMM).  This module will probably need to be at 
    41 least expanded.  A /dev file interface would probably be more effective.  
     53of an EEPROM (on a SDRAM DIMM). However, it will access serial EEPROMs 
     54on any I2C adapter. This module will probably need to be 
     55expanded.  A /dev file interface would probably be more effective.  
    4256This module was a programming exercise to get used to the new project 
    4357organization laid out by Frodo, but it should be at least completely 
    4458effective for decoding the contents of EEPROMs on DIMMs.  
    4559 
     60DIMMS will typically contain a 24C01A or 24C02. The other devices 
     61will not be found on a DIMM because they respond to more than one 
     62address. 
     63 
     64DDC Monitors may contain any device. Often a 24C01, which responds 
     65to all 8 addresses, is found. See the 'ddcmon' driver which has 
     66specialized /proc entries for DDC monitors. If the eeprom driver is 
     67loaded before the ddcmon driver and there is no 'ignore' line in the 
     68/etc/sensors.conf file, the eeprom driver will latch onto the DDC monitor 
     69eeprom. 
     70 
     71 
    4672Lacking functionality: 
    4773 
    48 * Read past byte 128.  There is no technical restriction for not doing 
     74* Read bytes 128-255.  There is no technical restriction for not doing 
    4975this, but making a zillion dataxx-xx files would be a bit rediculous.  
    5076EEPROMs on DIMMs shouldn't use the contents past byte 128, so we are fine.  
     77 
     78* Full support for larger devices (24C04, 24C08, 24C16). These are 
     79not typically found on a PC. These devices will appear as separate 
     80devices at multiple addresses, with every other 128-byte block inaccessable 
     81because of the missing 128-255 functionality. 
     82 
     83* Support for really large devices (24C32, 24C64, 24C128, 24C256, 24C5412). 
     84These devices require two-byte address fields and are not supported. 
    5185 
    5286* Enable Writing.  Again, no technical reason why not, but making it easy 
    5387to change the contents of the EEPROMs (on DIMMs anyway) also makes it easy 
    5488to disable the DIMMs until the values are restored somehow.  
     89 
    5590 
    5691Use: