Logo SB180
SB180 Headers SB180 Jumpers
J1, Reset JP1, EPROM Size Select
J2, Printer Port Header JP2, DRAM Chip Size Select
J3, Console Serial Port Header JP3, CTS0 Signal
J4, Modem Serial Port Header JP4, CTS1/DCD0 Signal
J5, XBUS I/O Expansion Header JP5, CTS/DCD Signal
J6, I/O Port Select Header JP6, Force READY
J7, Power Connector JP7, Fixed/Variable Write Precompensation
J8, 8" Floppy Disk Interface Header JP8, Write Precompensation
J9, 3.5"/5.25" Floppy Disk Interface Header JP9, Single Sided Operation
* JP10, Mixed Drive Size Operation

J1, Reset
            DESCRIPTION     PIN #     DESCRIPTION
           ------------     -----     ------------
+5, through 10k pull-up     1   2     GND
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J2, Printer Port Header
            DESCRIPTION     PIN #     DESCRIPTION
           ------------     -----     ------------
                -STROBE     1   2     GND
                     D0     3   4     nc
                     D1     5   6     nc
                     D2     7   8     nc
                     D3     9  10     nc
                     D4     11 12     nc
                     D5     13 14     nc
                     D6     15 16     nc
                     D7     17 18     nc
                   -ACK     19 20     nc

             nc = no connection (pin is floating)
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J3, Console Serial Port Header
NOTE: This header's pins are numbered so that a ribbon-cable pin-header connector can be used on one end of a ribbon cable and a ribbon-cable DB25 can be used on the other end of the cable, and the DB25 pin numbers will be 'preserved' correctly on the J3 pin header.
            DESCRIPTION     PIN #     DESCRIPTION
           ------------     -----     ------------
                     nc     1  14     nc
                    RxD     2  15     nc
                    TxD     3  16     nc
                    CTS     4  17     nc
                     nc     5  18     nc
                     nc     6  19     nc
                    GND     7  20     nc
                     nc     8  21     nc
                     nc     9  22     nc
                     nc     10 23     nc

             nc = no connection (pin is floating)
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J4, Modem Serial Port Header
NOTE: This header's pins are numbered so that a ribbon-cable pin-header connector can be used on one end of a ribbon cable and a ribbon-cable DB25 can be used on the other end of the cable, and the DB25 pin numbers will be 'preserved' correctly on the J4 pin header.
            DESCRIPTION     PIN #     DESCRIPTION
           ------------     -----     ------------
                     nc     1  14     nc
                    TxD     2  15     nc
                    RxD     3  16     nc
                    RTS     4  17     nc
                    CTS     5  18     nc
                     nc     6  19     nc
                    GND     7  20     DTR
                    DCD     8  21     nc
                     nc     9  22     nc
                     nc     10 23     nc

             nc = no connection (pin is floating)
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J5, XBUS I/O Expansion Header
            DESCRIPTION     PIN #     DESCRIPTION
           ------------     -----     ------------
              +5VDC PWR     1   2     +5VDC PWR
                    GND     3   4     GND
                    -RD     5   6     PHI
                    -WR     7   8     -RESET
                      E     9  10     -LIR
                   -NMI     11 12     -EXP SEL (E0-FF)
                  -WAIT     13 14     nc
                  -INT0     15 16     -HALT
                     ST     17 18     nc
                     A0     19 20     A1
                 -TEND0     21 22     A2
                     A3     23 24     A4
                 -DREQ0     25 26     -I/O ENABLE
                   8MHZ     27 28     RESET
                     D7     29 30     D6
                     D5     31 32     D3
                     D4     33 34     D2
                     D1     35 36     D0
                    GND     37 38     GND
                     nc     39 40     nc

             nc = no connection (pin is floating)
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J6, I/O Port Select Header
This is a single-row pin header, which was not populated on the SB180, and as far as I know, was not used. The 74LS156 decoder chip was also not installed. This header provided eight decoded I/O port select lines, E0 through E7.
            DESCRIPTION     PIN #
           ------------     -----
                    -E7     1
                    -E6     2
                    -E5     3
                    -E4     4
                    -E3     5
                    -E2     6
                    -E1     7
                    -E0     8
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J7, Power Connector
The power connector is usually the same connector found on 3.5" floppy disk drives, making it convenient to use standard PC power supplies with this board.
            DESCRIPTION     PIN #
           ------------     -----
                 +12VDC     1
                    GND     2
                    GND     3
                  +5VDC     4
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J8, 8" Floppy Disk Interface Header
            DESCRIPTION     PIN #     DESCRIPTION
           ------------     -----     ------------
                    GND     1   2     -LOW CURRENT
                    GND     3   4     -FAULT RESET (not used)
                    GND     5   6     -FAULT       (not used)
                    GND     7   8     -MOTOR ON 2  (not used)
                    GND     9  10     -TWO SIDED
                    GND     11 12     -MOTOR ON 1  (not used)
                    GND     13 14     SIDE SELECT (0/-1)
                    GND     15 16     -MOTOR ON 0  (not used)
                    GND     17 18     -HEAD LOAD 0
                    GND     19 20     -INDEX
                    GND     21 22     -READY
                    GND     23 24     -HEAD LOAD 1 (not used)
                    GND     25 26     -DRIVE SELECT 0
                    GND     27 28     -DRIVE SELECT 1
                    GND     29 30     -DRIVE SELECT 2
                    GND     31 32     -DRIVE SELECT 3
                    GND     33 34     DIRECTION
                    GND     35 36     -STEP
                    GND     37 38     -WRITE DATA
                    GND     39 40     -WRITE GATE
                    GND     41 42     -TRACK 0
                    GND     43 44     -WRITE PROTECT
                    GND     45 46     -READ DATA
                    GND     47 48     -HEAD LOAD 2 (not used)
                    GND     49 50     -HEAD LOAD 3 (not used)
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J9, 3.5"/5.25" Floppy Disk Interface Header
            DESCRIPTION     PIN #     DESCRIPTION
           ------------     -----     ------------
                      ?     1   2     ?
                    GND     3   4     HEAD LOAD/-IN USE
                    GND     5   6     -DRIVE SELECT 3
                    GND     7   8     -INDEX
                    GND     9  10     -DRIVE SELECT 0
                    GND     11 12     -DRIVE SELECT 1
                    GND     13 14     -DRIVE SELECT 2
                    GND     15 16     -MOTOR ON
                    GND     17 18     DIRECTION
                    GND     19 20     -STEP
                    GND     21 22     -WRITE DATA
                    GND     23 24     -WRITE GATE
                    GND     25 26     -TRACK 0
                    GND     27 28     -WRITE PROTECT
                    GND     29 30     -READ DATA
                    GND     31 32     -SIDE SELECT (0/-1)
                    GND     33 34     -READY
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JP1, EPROM Size Select
This jumper connects pin 27 (A14) of the EPROM socket to either a 4.7k pull-up (8/16k setting, the default), or to address line A14 (32k setting).
NOTE: This jumper's default setting is "hard wired", there is a circuit board trace installed between the two specified pads. To change the setting you will need to cut this trace and install a jumper as needed.
JP1 Image


          Yellow: for 8k or 16k EPROM (default)

             Red: for 32k EPROM



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JP2, DRAM Chip Size Select
This jumper connects pin 1 (A8) of the DRAM sockets to either a 4.7k pull-up (64k setting), or to multiplexed address line pin 9 of U13 (256k setting, the default).
NOTE: This jumper's default setting is "hard wired", there is a circuit board trace installed between the two specified pads. To change the setting you will need to cut this trace and install a jumper as needed.
JP2 Image


          Yellow: for 256k DRAM chips (default)

             Red: for 64k DRAM chips



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JP3, CTS0 Signal
This jumper connects the processor input pin 43 (CTS0) to either GND or J4 pin 5 (the default).
NOTE: This jumper's default setting is "hard wired", there is a circuit board trace installed between the two specified pads. To change the setting you will need to cut this trace and install a jumper as needed.
JP3 Image


          Yellow: for CTS0 to J4 pin 5 (default)

             Red: for CTS0 to GND



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JP4, CTS1/DCD0 Signal
This jumper connects the processor input pin 52 (CTS1) to either GND (the default), or to J4 pin 8 (DCD) or J3 pin 4 (CTS), depending on the setting of JP5.
This jumper connects the processor input pin 44 (DCD0) to either GND, or to J4 pin 8 (DCD, the default) or J3 pin 4 (CTS), depending on the setting of JP5.
NOTE: This jumper's default setting is "hard wired", there is a circuit board trace installed between the two specified pads. To change the setting you will need to cut this trace and install a jumper as needed.
JP4 Image


          Yellow: for CTS1 to GND, JP5 signal to DCD0 (default)

             Red: for DCD0 to GND, JP5 signal to CTS1



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JP5, CTS/DCD Signal
This jumper provides the "input signal" to JP4, connecting it to either J4 pin 8 (DCD, the default) or J3 pin 4 (CTS).
NOTE: This jumper's default setting is "hard wired", there is a circuit board trace installed between the two specified pins. To change the setting you will need to cut this trace and install a jumper as needed.
JP5 Image


          Yellow: for DCD to JP4 (default)

             Red: for CTS to JP4



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JP6, Force READY
This jumper (when installed) connects J8 pin 22 and J9 pin 34 (-DRIVE READY) to GND, thus forcing the FDC input pin 35 (READY) true. The default condition is "not installed".
This jumper may be needed by older drives which do not provide a READY signal.
NOTE: This jumper's default setting is "hard wired", there is a circuit board trace installed between the two specified pins. To change the setting you will need to cut this trace and install a jumper as needed.
JP6 Image


          Yellow: (not shown, default)

             Red: force READY



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JP7, Fixed/Variable Write Precompensation
This jumper determines whether the write precompensation signal to the FDC is fixed (tied high through a 4.7k pull-up, the default), or variable (controlled by the FDC -R/W/SEEK and LCT/DIR signals). When "fixed" write precompensation is applied to all tracks, when "variable" it is applied only on the inner tracks. See JP8 also.
NOTE: This jumper's default setting is "hard wired", there is a circuit board trace installed between the two specified pins. To change the setting you will need to cut this trace and install a jumper as needed.
JP7 Image


          Yellow: Fixed write precompensation (default)

             Red: Variable write precompensation



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JP8, Write Precompensation
This jumper determines whether the write precompensation signal to the FDC is off (tied to GND, the default), or fixed/variable (controlled by JP7). The SB180 manual says "See the SMC 9266 manual for full specifications."
NOTE: This jumper's default setting is "hard wired", there is a circuit board trace installed between the two specified pins. To change the setting you will need to cut this trace and install a jumper as needed.
JP8 Image


          Yellow: no write precompensation (default)

             Red: Fixed/Variable write precompensation, as determined by JP7.



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JP9, Single Sided Operation
This jumper allows the use of only single sided floppy drives.
NOTE: This jumper's default setting is "hard wired", there is a circuit board trace installed between the two specified pins. To change the setting you will need to cut this trace and install a jumper as needed.
JP9 Image


          Yellow: ? (default)

             Red: ?



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JP10, Mixed Drive Size Operation
This set of jumpers allows the processors TXS output signal to control 5.25" drive motors or selection of 5.25"/8" data transfer rates.
NOTE: Early SB180s have this jumper's default setting "hard wired", there is a circuit board trace installed between the specified pins. To change the setting you will need to cut these traces and install jumpers as needed. Later SB180s had a pin header installed, with jumper blocks.
JP10 Image


          Yellow: for system with only 3.5"/5.25" floppy drives (default)

             Red: for systems with a mix of 3.5"/5.25"/8" drives

            Blue: for systems with only 8" floppy drives

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