ACER AMERICA CORPORATION

HMB-16/20

Card Type          Memory
Chipset/Controller N/A
I/O Options        None
Maximum DRAM       8MB (4MB on HPB supplemental memory card)

[Image]

                   STARTING ADDRESS

          Address                     JP1

  1.25MB (1MB system RAM)      Pins 1 & 2 closed

  4.25MB (4MB system RAM)      Pins 2 & 3 closed

                               PARITY CHECK

                Enabled                                 JP2

  »                Enabled                       Pins 2 & 3 closed

                  Disabled                       Pins 1 & 2 closed

             MEMORY SIZE

   Size      SW1/1    SW1/2    SW1/3

    2MB       On       On       On

    4MB       Off      On       On

    6MB       Off     Off       On

    8MB       Off     Off      Off

                         MEMORY READ/WRITE TIMING

      Card Model/System Speed             SW1/4               TP1

  »          HMB-16/100-ns                 On           Pins 4 & 9, 3 & 8
                                                             closed

  »           HMB-20/85-ns                 On           Pins 4 & 9, 1 & 6
                                                             closed

              HMB-16/85-ns                 Off          Pins 4 & 9, 3 & 9
                                                             closed

             HMB-20/100-ns                 On           Pins 4 & 9, 1 & 6
                                                             closed

  Note: SW1/4 in the on position enables the zero wait state.

                            DRAM CONFIGURATION

   Size      Bank 0       Bank 1       Bank 2      Bank 3        Parity
                                                                 Bits

   2MB         (16)        None         None        None       (8) 511000
             514256

   4MB         (16)         (16)        None        None       (8) 511000
             514256       514256

   6MB         (16)         (16)        (16)        None       (8) 511000
             514256       514256       514256

   8MB         (16)         (16)        (16)         (16)      (8) 511000
             514256       514256       514256      514256

  Note:(1) Banks 2 & 3 are located on the HPB daughter card.

  (2) The HMB-16 uses 100-ns 514256 RAM chips and 100-ns 511000 parity
  chips.

  (3) The HMB-20 uses 85-ns 514256 RAM chips and 85-ns 511000 parity
  chips.

                    MISCELLANEOUS TECHNICAL NOTES

  The HMB-16/20 is for use only in Acer interleaved-memory systems.