Cpu And Power Supply Board (No. 7094); Power Supply; Processor Addressing Configuration - GE 325 Product Manual

SECTION 7
CPU AND POWER SUPPLY BOARD
(NO. 7093)
Power Supply
AC line power for the simulator enters through connector J3
which protrudes through the rear panel. For 110-120 VAC
operation, one 0.2 A slow-blow fuse, F1, is installed in the hot
side of the line, and jumper W6 is installed in the neutral side.
For 220-240 VAC operation, two 0.2 A super-time lag fuses,
F2 and F3, are installed in both sides of the line.
Power passes through the power switch and the line filter
before being applied to the primary winding of transformer
TI. For 110-120 VAC operation, jumpers W7 and W8 are
installed; for 220-240 VAC operation, jumper W9 is
installed. One secondary winding is full-wave rectified,
filtered, and regulated to provide the +5 V supply. The other
secondary winding is full-wave bridge rectified, filtered, and
regulated to provide dual +15 V and -15 V supplies. Pin 8
on the secondary winding also supplies a +16 VAC signal to
Ji which is used to drive the ECG CMR circuitry on the
Analog Switch Board (No. 14118).
Processor Addressing Configuration
The simulator uses an 8085A microprocessor (U2). The eight
bits of the processor's address/data bus are input to U3 which
latches them with the ALE signal to produce the lower eight
bits of the address bus. The three highest order bits are
decoded by one half of U12 to provide four chip enables,
each containing 2000H addresses. One of these enables is
further decoded by the other half of U12 with the next two
bits of the address bus to provide four more enables, each
containing 800H addresses. An additional enable signal is
generated by U7 (pin 8) which inverts the highest-order bit of
the address bus. Refer to Table 7-1 for a summary of address
selections.
Table 7-1. Processor Addressing
| MEMORY ADDRESS (HEX) DEVICE SELECTION © FUNCTION
| oooo-1FFF U4 (2764) Program PROM
2000-20FF U6 (8155) RAM
4000 U11.(7528) ECG D/A Converter
4001 U11 (7528) External D/A Converter
6000 U10 (7524) UA D/A Converter
6800 U15 (7524) Manual Adjustment A/D Converter
7000 Spare
7800 Spare |
8000-FFFF US (2756) HR/UA Pattern PROM
МО 20 U6 (8155) Command Register
VO 21 U6 (8155) | Port A: Switch Inputs
VO 22 U6 (8155) | Port 8: Switch Inputs
VO 23 U6 (8155) | Port C: Mode Outputs
МО 24 U6 (8155) ! Timer Count, Low Byte
VO 25 U6 (8155) ! Timer Count, High Byte
7-2 © Theory of Operation