PMAC Product Guide • If a jumper is ON, the value it contributes to the base address is zero. • If a jumper is OFF, the value it contributes to the base address is given in the table above. On the PMAC-Lite, the jumpers are physically arranged in the same order they are presented in the above table. From Jumper Configuration To Address To determine the address specified by a given jumper configuration, use the following formula:
(Decimal) Address = 2048*E91 + 1024*E92 + 512*E66 + 256*E67 + 128*E68 + 64*E69 + 32*E70 + 16*E71 (Hexadecimal) Address = $800*E91 + $400*E92 + $200*E66 + $100*E67 + $80*E68 + $40*E69 + $20*E70 + $10*E71 In each case, Exx = 1 if the jumper is OFF; Exx = 0 if the jumper is ON. Example: On a PMAC card, the jumpers are in the following configuration: The address can be computed as: Decimal Address = 0 + 0 + 512 + 256 + 0 + 0 + 0 + 0 = 768 Hex Address = 0 + 0 + $200 + $100 + 0 + 0 + 0 + 0 = $300 From Address To Jumper Configuration Once an I/O address on the PC expansion port has been selected, the following procedure can be used to set the address jumpers. 1.
Convert the address to a 3-digit hexadecimal value ($000 to $FFF, representing 0 to 4095). If the value does not fit in this range, PMAC cannot be set for this address. Make sure the last digit is 0; only addresses divisible by 16 are permitted as PMAC base addresses. 2. Take the first hex digit and convert it to binary. The binary digits represent bits 11 through 8 of the base address. Assign each binary digit to jumpers as follows: 3. Take the second hex digit and convert it to binary. The binary digits represent bits 7 through 4 of the base address. Assign each binary digit to jumpers as follows:
PMAC Jumper Configuration 17 Jumper E91 E92 E66 E67 E68 E69 E70 E71 Bit # 11 10 9 8 7 6 5 4 Dec Value 2048 1024 512 256 128 64 32 16 Hex Value 800 400 200 100 80 40 20 10 E91 E92 E66 E67 E68 E69 E70 E71 ON ON OFF OFF ON ON ON ON Bit # 11(MSB) 10 9 8(LSB) Jumper E91 E92 E66 E67 Digit Value 8 4 2 1 Setting for 1 OFF OFF OFF OFF Setting for 0 ON ON ON ON