005-038601 – SCSI II Controller (6786 / 6787)

SW9 is a six position DIP switch that selects the HBA hard device code referred to as Device ID 0. The switches are read by the HBA IOP through the default register (Switch ON is logic 0, Switch OFF is logic 1):

SW9-1 BIT POSITION 5 (MSB)
SW9-2 BIT POSITION 4
SW9-2 BIT POSITION 3
SW9-4 BIT POSITION 2
SW9-5 BIT POSITION 1
SW9-6 BIT POSITION 0 (LSB)

The recommended HBA hard device code is 13 (octal) or 001011 (binary) and the recommended secondary HBA hard device code is 53 (octal) or 101011 (binary).

SW9-1 thru SW9-6 = 110100 for hard device 13 (octal)
SW9-1 thru SW9-6 = 010100 for hard device 53 (octal)  

SW14 is a four position DIP switch that selects the HBA default device type and the SCSI bus device identification (DID). This default device type is specified by a single bit that indicates if the device is masked out as a tape or disk device. The default device type can be read along with the hard device code through the default device register. The SCSI bus DID is specified by three bits that select a SCSI DID number from 0 thru 7; the DID can be read through the SCSI status register. (Switch ON is logic 0, Switch OFF is logic 1):

SW14-1 ON = Disk, OFF = TAPE (configurations of both Disk and Tape should select DISK)
SW14-2 SCSI DID bit position 2 (MSB)
SW14-3 SCSI DID bit position 1
SW14-4 SCSI DID bit position 0 (LSB)

In most configurations the HBA should have a SCSI DID of 7 or 111 which is the highest priority device on the SCSI bus. To achieve this SCSI DID set SW14-2,SW14-3 and SW14-4 to 000

SW15 is a four position DIP switch that selects the HBA ID on the BMC bus. Most EXLIPSE MV family BMC computers permit as many as 8 BMC controllers to be configures on the host BMC bus. Models 6786 and 6787 HBA’s can be assigned any priority on the BMC bus from 0 thru 7. Three positions of SW15 are used to assign the BMC ID number to the HBA. (Switch ON is logic 0, Switch OFF is logic 1):

SW15-1 Not Used
SW15-2 BMCCR2 (MSB)
SW15-3 BMCCR1
SW15-4 BMCCR0 (LSB)

SW1, SW2, SW3, SW4, SW5, SW6, SW7, SW8, SW10, SW11, SW12 and SW13 select either single-ended mode or differential mode of SCSI operation. The switches are arranged in two banks, one bank SW10 thru SW13 routes the SCSI bus signals from the SCSI controller either to differential transceivers or to terminators. The other bank of switches, SW1 thru SW8 selects either outputs of the differential transceivers or the single ended bus signals and routes the signals to the back-plane. 

Each of the switches should be set one way of the other as marked on the HBA PCB SE or DIFF. 

One bit in each switch is used to allow the hardware to determine the switch setting. The switch settings can be read by the IOP through the SCSI status register to check that all the switches are set the same way.