Reset Circuit - Epson LQ-1070 Service Manual

Location
2A
5E
PROM
6E
RAM
3E
MROM
(Mask ROM) 4E
Vref Circuit —
2.3.2 Reset
Circuit
Figure 2-19 shows the reset circuit in block diagram form. The reset circuit issues the RESET signal.
Each part of the control circuits is initialized when this RESETsignai is received. The conditions when
the RESET signal is output are described below.
When turning on the power supply
Immediately after
the STK-6022B is then discharged. After this, STK-6022"B outputs the THLD signal, and E05A50 then
outputs the RESET signal. After a certain time has elapsed, the charge in the condenser in the
Resets performed by the CPU itself (CPU self-reset)
The CPU outputs the RESET signal if there is a RESET request for E05A50 and if E05A50 has output
the DISC pulse.
Table 2-5. Functions of the Main IC and Circuits (Cont.)
This is a
single
and MOTOR, PF of the PRINTER MECHANISM. The chip also includes the
various sensor input circuits for the PRINTER MECHANISM.
PROM contains the program that runs the CPU.
Holds the CPU working area and the various buffers. (1 E is not used for
an 80-column device and is not installed.)
Holds the character design (also called the character generator).
information as the TOF position.
This is a circuit for generating the reference voltage used in the A/D
convertor within the CPU.
the power has been turned on, STK-6022B (2A) outputs the VCCON pulse. E05A50
+5 v.
L i n e
(2A)
- - - - - - - - - - -
75
7 3
—
DISC
Figure 2-19. Reset Circuit Block Diagram
Functions
chip that houses drive circuits for the printhead, MOTOR,CR
- - - - - - - - - - -
107
106 —
0 5
'
2-15
REV.-B