Troubleshooting
2-20
2.11.3
IEEE-488 bus tests
The IEEE-488 interface in the Model 2002 consists of the 9914 GPIA chip (U622) and the
75160 (U621) and 75161 (U623) bus drivers. The 75160 buffers the data lines (DIO1-DIO8),
and the 75161 buffers the bus handshake lines and other control signals. The circuitry to test
these components is contained in the 5064 ASIC (U618).
Test 104.1 — Handshake
Type
Pass/Fail
Fault message
IEEE-488 handshake failure
Description
Circuitry in the 5064 (U618) is set up to simulate an IEEE-488 handshake. Bytes are written to
the 9914 (U622) Data Out register, and the interrupt status register is checked to verify that a
Byte-Out handshake is completed.
These tests verify the basic functionality of the 9914, 75161 and the handshake portion of the
ASIC (Signals BNRFD, BNDAC, and BDAV).
Drawing reference
Digital Board; 2002-140
Components
U618, U622 and U623.
Test 104.2 — Data
Type
Pass/Fail
Fault message
IEEE-488 data failure
Description
For this test, bytes are written to the 9914 Data Out register (U622) to drive and release bus line
DIO1. The state of this signal is verified at the 68302 (U631) through PB0 (BITB1). This test
verifies the basic functionality of the 9914 and 75160 (U621).
Drawing reference
Digital Board; 2002-140
Components
U612 and U622
