Epson LQ-860 Technical Manual page 78

2.3.1.3 Font/Identity Module Installation and Removal Reset
Figure 2-24 shows the reset circuit and Figure 2-27 shows the module installed/removed reset timin9.
The font and identity modules should not be installed or removed while the power is on. If this is done, the
ROUT signal must be set low to prevent a JIJNMM board circuit malfunction.
After reset, the CPU starts execution and selnds a RD signal to the memory devices. The reset circuit in
the MMU counts 32 x RD pulses and then generates a RDCLK pulse. When a module is installed or
removed, the exclusive OR value of CAR1 and CAR2 changes from the reset default value, and the DISC
signal is set low by the rising edge of the sec:ond pulse of the synchronized RDCLK signal. Consequently,
the THLD voltage begins decreasing. When the THLD voltage drops to VN, the DISC signal goes high and
then begins increasing. When it rises to VP, the ROUT signal goes high and the CPU restart.
Also, Table 2-20 shows the relationship between the input at CARI and CAR2 of MMU (8B) and the state
of the mudule.
DISC
ROUT
CAR1"CAR2
RD CLK ~;
1
I
I
(
I
I
1 1 1 1 1 - &
1 2
A CARTRIDGE: IS
Figure 2-27. Module Installed/Removed Reset Timing
,
I
I
I
I
I
I
A CARTRIDGE IS REMOVED/
INSTALLED
2-31
REV.-A
- -
- -
- -