Cpu - Epson TM U200D - B/W Dot-matrix Printer Technical Manual

RS-232 serial interface:
IEEE 1284 parallel interface:
CN4
#RST 29
DSR_RESET 28
#25_RESET 27
CN4 pin 29 is the reset signal of the IEEE 1284 parallel interface circuit board.

CPU

The printer uses an external 8-bit and internal 16-bit CPU, with an external clock of 14.7 MHz.
The CPU (U5) controls the internal processing of the printer according to the printer control
program written in EPROM (U8).
CPU pin functions
Pin CPU
No. Function
1 P57
2 NMI
3 P100
4 P101
5 AVCC
6 AVSS
7 P60/AN0
8 P61/AN1
2-18 Mechanism Configuration and Operating Principles
Two signals can be selected (DSR signal or pin 25 input signal).
Pin 25 RESET signal must be used. DIP switch 2-4 is fixed to ON.
The printer can be reset with the nInit signal (pin 31) from the
host.
Q31
DSW2
D16
3
4
D1
Figure 2-19 Reset circuit
Signal Name I/O Level
ELED/DSW9 I/O TTL
NMI I TTL
AC1/DSEL O TTL
AC 2/DSEL O TTL
AVCC I (+5V)
AVSS I (0V)
V DTC I Analog
HD TEMP I Analog
{5 V
R50
{5 V
U9
1
IN
C42
+
4
C
C28
_
R49
C26
Q32
Description
ERROR LED Low: on
DIP SW 2-1 read when P100, P101 is low
Not used (Connected to +5V directly)
Auto cutter drive (1) and DIP SW read selection
Low: read (read once after the initialization)
High: break status when used as motor control
port
Auto cutter drive (2) and DIP SW read selection
Low: read (read once after the initialization)
High: break status when used as motor control
port
This pin must be changed at the same time as
P100.
Analog/digital convertor standard voltage
(Analog/digital convertor) GND terminal
+24V power voltage detection
Head temperature detection
{5 V
U5
D26
5 21
OUT RESET
3
GND
C27
Rev.B