4.Controlsystem - Ikegami HTM-1550R Service Manual

4. CONTROL SYSTEM
4-1 FRONT PANEL BOARD and Others
(1) Outline
Th.is syslem reads the positioning data of each switch. rotary en-
coder and remote number on the fronl panel, and transmits them to
the CPU on the MPU BOARD. The CPU con!rols each IBD,
etc ..
(2) Circuit description
(a) Swilch matrix circuit
The switches on the front pane] are of a matrix configuration and
consist of I Cl and IC2. I Cl and 1C2 are provided for encoder.
When pres.5 the swilch is pressed, lhe output turns into a 6-bit axle,
which is read in CPU.
When the switch Pin 15 of IC2 outputs "H" at this moment, CPU
interrupts the program and reads the switch code.
(b)
1/0
proc,ssing
The address bus connecting from the MPU BOARD is allocated lo
address 8 ($2000~$2007) by the address decoder of IC4 and
1atches each inpuVoutput port.
The Jatched data is transmined 10 CPU through the data bus con-
necting from the MPU BOARD.
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