1-9. IC11 FAS236U (SCSI Controller) 1-9-2. Pin Descriptions SERVICE MANUAL 25 Pin No. Signal name Dir Explanation 100 DREQ out DMA request. H: ready to transfer data. 1 /DACK in DMA acknowledge. 2 /DBWR in Data-bus write control. 4 IGS out Indicates that chip is acting in initiator mode. 5 DIFFSENS in H: differential mode. 6 TGS out Indicates that chip is acting in target mode. 7 EDIFFS in H: Enable “DIFFSENS” function. 8-15 DB[15:0] i/o DMA data-bus. 19-26 16,27 DBP[1:0] i/o DMA data-bus parity. 29-36 /SDI[7:0] in SCSI data bus. 37 /SDIP in SCSI data parity. 42-45 /SDO[7:0] out SCSI data bus. 48-51 52 /SDOP out SCSI data parity. 56 /SELO out SCSI bus select. 57 /BSYO out SCSI bus busy.
58 /REQO out SCSI bus request. 59 /ACKO out SCSI bus acknowledge. 62 /MSG i/o SCSI bus message phase. 63 /CD i/o SCSI bus control and data phase. 64 /IO i/o SCSI bus I/O phase. 65 /ATN i/o SCSI bus attention. 66 /RSTO out SCSI bus reset. 69 /SELI in SCSI bus select. 70 /BSYI in SCSI bus busy. 71 /REQI in SCSI bus request. 72 /ACKI in SCSI bus acknowledge. 73 /RSTI in SCSI bus reset. 74,75 MODE[1:0] in Bus configuration mode select. 76 /INT out Interrupt output. 77 RESET in Power reset. 79 /WR in Write control. 80 /RD in Read control. 81 /CS in Chip select. 82-85 A[3:0] in Address bus. 86 CLK in Internal chip timing clock. 87 /DIFFM in H: single-endes mode. L: differential mode.
90-93 PAD[7:0] i/o PAD bus. Connected with CPU for communication. 96-99 38,88 VDD - +5V DC power input. 17,18,40 Vss - GROUND. 0V DC power return. 41,46,47 54,55,60 61,67,68 94,95