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

8D77 (4-4) SCSI SE High Performance Internal/External I/O Controller FC 2410, 2831

WD33C93B Datasheet

(52G5484, 52G5483, 52G7504, 52G7509, 11H4779, 11H4780, 52G1171, 2410, 2830)

SCSI-2 SE I/O Controller (Type 4-4):

  OK, what do we got?

What the 4-4 supports:
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  [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 [Oh YES! YES!]

SCSI I/O Controller 4-4, FRU 52G5483


D1 - Diode
DL1,2 bel 0401-1403-11
F1 PTC
J1 - High Availability
U9 WD33C93BJM 00-02 or 00-04
U4 32G0215ESD Big silver chip
U5,6 CXK581001M-70L
U8 N80C186XL20
U22 uCode??
U26 PLCC44 ???
U47 ??
Y2 39.9500 MHz

All versions of the 4-4 use 32G0215ESD [Entry Systems Division]. 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

32G0215ESD MCA Bus interface ???

DL1,2 bel 0401-1403-11 High-Speed 4 Pin SIP Passive Delay Module
   0401-1403-11 Total Delay 5.0 +/- 0.25 ns, Rise Time (True) 1.1 ns, DCR Max 1.0 Ohm

bel App 1-R1 Pulse Shaping / Clock Pulse Generation Circuits

Y2 is a 39.9500 MHz osc, that provides an input clock to 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 J1headers? DIP or SIP resistor network?

SCSI TERMINATORS (Purpose and Usage)

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.

SCSI Termination 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


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  ?


Stephan Goll says:
   To make a summary: AIX has a database called ODM. In this database there are the definitions and suggestions for configuring all the cards not configured before IPL. Cards where AIX can boot from, well, should be configured somehow, I believe by the ROS (or BIOS). Makes sense, because only the ROS knows from where the box can IPL. And remember, AIX uses a two stage boot process, first it boots in minimal mode, configures the cards using the ODM, and then it boots again with the system fully configured (so it is written in my AIX survival guide).


Overload Protection and Terminator Power (Term Power)
   The SCSI controller provides term power for the SCSI bus; connect devices to the bus so they do not provide term power. The controller uses a fuse that must be replaced after failure.

   Do not connect or disconnect any SCSI device while power is on. Such “hot plugging” is forbidden because this practice may blow the controller fuse, corrupt data or permanently damage SCSI controller chips in controllers or devices.

  The fuse on an SCSI controller protects the external and internal SCSI bus. The fuse may be blown by a defective cable, terminator, or device attached to the controller, but not by a defective controller.

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