TM 11-6625-3145-14
Maintenance: Troubleshooting-318/338 Service
Function 3 includes nine test programs. These programs transmit increment pattern data from SIO Port-B, then receive
and compare that data against the original data. Data speed is changed automatically from 110 baud through 9600 baud.
(The test data format is fixed at eight bits/word, even parity, and one stop bit.)
Description - Refer to the 318S1/338S1 I/O function list, and simplified block diagrams when reading the following.
The I/O address of the SIO and other 318S1/338S1 hardware is decoded by U30. The SIO Port-B controls RS-232
functions; that address is 92 and 93, and the RS-232 baud rate selector address is 88.
The SIO data line is common to both Port-A and Port-B. These eight data lines connect to buffer U25; U25 is gated by the
318S1/338S1 I/O address.
The SIO timing is synchronized by the CPU clock which is supplied from the MPU on the A06 board through bus connector
31A. Its waveform is adjusted by U12 and U32 before reaching the SI0.
All but one of the MODEM control signals are controlled by SIO Port-B. The exception is the DSR signal, which appears in
the 318S1/338S1 status register at address 80. All the signals coming into Port-B are converted from RS-232-levels to
TTL levels by the receiver, U40; all outgoing signals are converted from TTL levels to RS-232 levels by the transmitter,
U41.
RS-232 data also passes through U40 and U41, and is sampled at 16 times the clock of the baud rate. This clock is
supplied by U5 (baud rate generator). U45 latches the baud-rate-select data and its output defines the clock rate.
An 1/0 loop mode is available for TSTRM2. This mode is used to check the I/O address selection circuit. When the
diagnostic program is running in the I/O loop mode, TSTRM2 executes the following program function continuously.
Table 7-11
318 RS-232C I/O ADDRESSES
Selected I/O Address
Program Function
80
Read content of address 80.
88
1. Write data 10 to address 88.
2. " 20
3. " 40
4. " 80
Repeat in rotation 1 through 4.
92
Write data 55 to SIO Port-B data
register.
93
1. Write data 18 (reset command)
to SIO Port-B register #0.
2. Read SIO Port-B register #0.
Repeat 1 and 2.
7-31
Summary of Contents for 318
Page 119: ...318 VERIFICATION AND ADJUSTMENT PROCEDURES ...
Page 182: ...338 VERIFICATION AND ADJUSTMENT PROCEDURES ...
Page 253: ...318 ___________________ TROUBLESHOOTING TREES ...
Page 344: ...338 TROUBLESHOOTING TREES ...
Page 517: ...TM 11 6625 3145 14 318 338 4434 923 318 Block Diagram ...
Page 518: ...TM 11 6625 3145 14 318 338 4434 924 338 Block Diagram ...
Page 519: ...TM 11 6625 3145 14 318 338 4434 925 318 Acquisition Module Wiring Diagram ...
Page 520: ...TM 11 6625 3145 14 318 338 4434 926 318 338 Mainframe Wiring Diagram ...
Page 521: ...TM 11 6625 3145 14 318 338 4434 926 338 Acquisition Module Wiring Diagram ...
Page 522: ...TM 11 6625 3145 14 318 338 4434 928 Figure 9 1 318 A01 Input A Board Component Locations ...
Page 526: ...TM 11 6625 3145 14 ...
Page 528: ...TM 11 6625 3145 14 Figure 9 3 318 338 A03 ACQ Control Board Component Locations ...
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Page 542: ...TM 11 6625 3145 14 Figure 9 8 318 338 A10 CRT Board Component Locations ...
Page 544: ...TM 11 6625 3145 14 Figure 9 9 318 338 A11 Inverter Board component Locations ...
Page 546: ...TM 11 6625 3145 14 Figure 9 10 318 338 A12 Regulator Board Component Locations ...
Page 551: ...TM 11 6625 3145 14 Figure 9 12 338 A01 Input A Board Component Locations ...
Page 553: ...TM 11 6625 3145 14 318 338 SERVICE ...
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Page 555: ...PIN 058584 ...