
COMPUTER MODULES, INC.

LPC SERIAL/2A

Card Type   Serial
Chip Set    Zilog
I/O Options Serial ports (2)
Data Bus    8-bit ISA

[Image]

                                CONNECTIONS

          Function            Label           Function            Label

  Serial port 1 (May be         J1       Serial port 2             J2
  RS-232, RS-422/423, or                 (RS-232 only)
  RS-485)

                        USER CONFIGURABLE SETTINGS

                   Setting                       Label         Position

     Factory configured - do not alter          SW1/1           Off

                       CLOCK SOURCE FOR PORT 1

              Setting                             JB3

  External clock from serial RTxC          Pins 1 & 2 closed

     Internal clock from 8254           Pins 1 & 3, 2 & 4 closed

                     DMA CHANNEL - RECEIVE

            Setting                           JB1

              DMA1                Pins 9 & 10, 13 & 14 closed

              DMA3               Pins 10 & 12, 14 & 16 closed

            Disabled                    Above pins open

                          DMA CHANNEL - TRANSMIT

               Setting                                JB1

                DMA1                      Pins 9 & 11, 13 & 15 closed

                DMA3                      Pins 11 & 12, 15 & 16 closed

              Disabled                          Above pins open

            Note: If a DMA is used for transmission then port 1 may not
            be used.

                             BASE I/O ADDRESS

  Setting     SW1/2    SW1/3   SW1/4    SW1/5    SW1/6    SW1/7    SW1/8

      000h     On       On       On       On       On       On       On

      008h     On       On       On       On       On       On      Off

      010h     On       On       On       On       On      Off       On

      018h     On       On       On       On       On      Off      Off

      020h     On       On       On       On      Off       On       On

     380h     Off      Off     Off       On       On       On       On

      3D8h     Off      Off     Off      Off       On      Off      Off

      3E0h     Off      Off     Off      Off      Off       On       On

      3E8h     Off      Off     Off      Off      Off       On      Off

      3F0h     Off      Off     Off      Off      Off      Off       On

      3F8h     Off      Off     Off      Off      Off      Off      Off

            Note: A total of 127 base address settings are available. The
            switches are a binary representation of the decimal memory
            addresses. SW1/2 is the Most Significant Bit and switch SW1/8
            is the Least Significant Bit. The switches have the following
            decimal values: SW1/8=8, SW1/7=16, SW1/6=32, SW1/5=64,
            SW1/4=128, SW1/3=256, SW1/2=512. Turn off the switches and
            add the values of the switches that are off to obtain the
            correct memory address. (Off=1, On=0)

                INTERRUPT

       Setting               JB1

   IRQ3 internally    Pins 1 & 2 closed

   IRQ3 from 8254     Pins 1 & 3 closed

   IRQ4 internally    Pins 2 & 4 closed

   IRQ4 from 8254     Pins 3 & 4 closed

   IRQ5 internally    Pins 5 & 6 closed

   IRQ5 from 8254     Pins 5 & 7 closed

   IRQ7 internally    Pins 6 & 8 closed

   IRQ7 from 8254     Pins 7 & 8 closed

                                PORT 1 TYPE

   Setting      JB4         U5           U6           U9          U10

   RS-232      Pins 1       Not        MC1489         Not        MC1488
               & 2, 4   installed                 installed
                 & 5
                open

  RS-422/423   Pins 1     26LS32         Not        26LS31         Not
               & 2, 4                installed                 installed
                 & 5
                open

   RS-485      Pins 1     26LS32         Not        26LS31         Not
               & 2, 4                installed                 installed
                 & 5
               closed

            PORT 1 PINS 9 & 10

       Setting               JB3

       +12V DC        Pins 7 & 8 closed

      Not used         Pins 7 & 8 open

         PORT 1 RS-422/423/485 DRIVER

        Setting                 JB3

    Enabled by RTS       Pins 5 & 6 closed

  Enabled permanently    Pins 3 & 5 closed

                   PORT 1 RS-422/423 DRIVER TERMINATION

      Setting              JB4               RP3               RP4

   Not terminated     Pins 5 & 6, 7     Not installed     Not installed
                       & 8 closed

     Terminated       Pins 5 & 7, 6       Installed         Installed
                       & 8 closed

            Note: The ohm values of RP3 and RP4 should be determined to
            cause a difference in voltage of at least 2.0V between the
            ends of the serial cable.

               8254 CLK0 SOURCE

        Setting                 JB2

   8254 clock signal    Pins 15 & 16 closed

       Disabled          Pins 15 & 16 open

               8254 CLK1 SOURCE

        Setting                 JB2

   8254 clock signal    Pins 13 & 14 closed

       8254 CLK0        Pins 11 & 13 closed

       Disabled           Above pins open

               8254 CLK2 SOURCE

        Setting                 JB2

   8254 clock signal    Pins 10 & 12 closed

       8254 CLK1         Pins 9 & 10 closed

       Disabled           Above pins open

                        CLK0 INTERRUPT GENERATOR

              Setting                               JB2

      CLK0 generates interrupt               Pins 7 & 8 closed

  CLK0 does not generate interrupt            Pins 7 & 8 open

                        CLK1 INTERRUPT GENERATOR

              Setting                               JB2

      CLK1 generates interrupt               Pins 5 & 6 closed

  CLK1 does not generate interrupt            Pins 4 & 6 open

                        CLK2 INTERRUPT GENERATOR

              Setting                               JB2

      CLK2 generates interrupt               Pins 1 & 3 closed

  CLK2 does not generate interrupt            Pins 1 & 2 open

                       MISCELLANEOUS TECHNICAL NOTE

            When using RS-422, resistors R2, R3, R5, and R6 must be
            installed to match the impedance of the cable that is used.
            The board will not function properly in RS-422 mode without
            these resistors.

