SCSI-2 SE High Performance Internal/External I/O Controller (Type 4-4)

SCSI I/O Controller 4-4
Term Power Overload Protection (4-1 page)


  • Accepts multiple commands per device at a time from system
  • SCSI-2 data rate of up to 10MB per second (synchronous protocol)
  • SCSI initiator
  • SCSI target
  • SCSI parity
  • Bus Master
  • Streaming Data Support (Ed. I think it MUST support Bus Fairness as well)
  • Address and Data Parity Support
  • Supports Command Tagged Queuing (as SCSI initiator)
  • Interrupt levels 3, 4, 5, 7, 10, 11, 12, 14
  • HPDB50 external SCSI Port

SCSI I/O Controller 4-4 Adapter ID 8D77, FRU P/N 52G5483

(P/N 52G5484, 52G5483, 52G7504, 52G7509, 11H4779, 11H4780, 52G1171; FC 2410, 2830)

D1 Diode
DL1,2 bel 0401-1403-11 delay module
J1 High Availability
U4 32G0215(ESD)
U5,6 CXK581001M-70L 128Kx8 SRAM
U8 N80C186XL20
U9 WD33C93BJM 00-02 or 00-04
U22 uCode??
U26 PLCC44 ???
U47 ??
Y2 39.9500 MHz osc (WD33C93B)

Only 74xx glue on the solder side.

U4 32G0215(ESD) is used on all versions. There seems to be a connection between the later production dates and the "00-04" revision of the WD33C93B.

32G0215 Laser Etched - 93-ish mfr, "00-02" WD33C93B
32G0215 Ink Printed - 95-ish mfr, "00-04" WD33C93B

DL1,2 bel 0401-1403-11 Passive delay module. Total Delay 5.0 ns
bel App 1-R1 Pulse Shaping / Clock Pulse Generation Circuits

Y2 39.9500 MHz osc, provides input clock for the WD33C93B
   "When the 33C93B has an input clock between 16 and 20 MHz, ... the host can select... Fast synchronous transfers with a peak rate of 10 MB/s on both the SCSI and host DMA interfaces."

I also suspect that 39.9500 MHz osc is used to provide the clock (suitably divided) for other components.

Three possible firmware chips, the socketed PLCC44 (U26), the socketed DIP-20 (U22), and the surface mounted PLCC (U47) above the 80C186XL20.

I see two digital signal regenerators (DL1,2) between the DIP-20 and the 32G0215.

J1 (also called P3) High Availability Jumper

Must be out of the circuit for high availability ("Y") configuration. Put the jumpers over one row only so you don't loose them. There are 13 pairs of pins. You will need a 6 and 7 pair berg jumper (ganged jumper) in order to use this for normal SCSI configuration.

P3 High Avail Jumper 2 pieces 42F7525, 42F7526

So, can we make a kludge of an internal terminator using the J1 headers? DIP or SIP resistor network?

FPT Terminators (from HERE)

Terminators: The FPT-3 is generally used on the the internal end of the cable, and the FPT-18 is used on the external end of the cable.

non-FPT: passive. Internal/External SCSI bus limited to two external devices.
FPT-3: actively terminates only three SCSI bus lines: ACK, REQ, SEL.
FPT-18: active. 18 lines of SCSI bus, [eight data lines]. No longer manufactured.
FPT-18+: active. 18 lines Functionally equivalent and fully interchangeable with FPT-18.

More on FPT Terminators (from HERE)

FPT is an even better form of active termination, in which diode clamps are added to eliminate signal overshoot and undershoot. The trick is that instead of clamping to +5 and ground, these terminators clamp to the output of two regulated voltages. This arrangement enables the clamping diodes to eliminate signal overshoot and undershoot, especially at higher signaling speeds and over longer distances. FPT is technically not found in the SCSI specifications but is a superior type of termination for SE applications that experience high levels of electrical noise.

FPT terminators are available in several versions. FPT-3 and FPT-18 versions are available for 8-bit standard SCSI (Figure 7.18 shows the schematic for an FTP-18 terminator), whereas the FPT-27 is available for 16-bit (Wide) SCSI. The FPT-3 version forces the three most highly active SCSI signals on the 8-bit SCSI bus to be perfect, whereas the FPT-18 forces all the SCSI signals on the 8-bit bus except grounds to be perfect. FPT-27 also forces all the 16-bit Wide SCSI signals except grounds to be perfect.

FPT-18 SCSI terminator schematic (click to enlarge)

Card edge, FPT-3 00G0972 "50-position card edge terminator"
70F9900 Old card edge non-FPT Terminator. Sub to 00G0972

External Terminator for HPDB50 Port

50-Position External Terminator FPT-18C 52G4259

50-pin, high-density, external, FPT-18+ 51G7737

Note: 52G4259 replaces FPT-3 00G2223, 51G7737, and FPT-18 43G0378. All are usable.

Aeronics 00G2223 FPT-3

52G4259 FPT-18C

52G4259 Black FPT-18C (different case)

Same P/N (52G4259) and EC (D18561). My SWAG is that IBM moved from the AMP metal shell to the black one due to cost. I can't verify the electronics being the same, but they probably are...

External Terminator for C50 Connector on External SCSI Cable
50-pin, low-density, external, FPT-18+ 51 51G7736
50-pin, low-density, external, FPT18C 52G4260

Note: 52G4260 replaces FPT-3 00G0968, FPT-18 43G0467, and FPT-18 51G7736. All are usable.

51G7736 FPT-18+

222-12-50-035 CINCH

FPT-18 43G0378?

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