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.