Epson TM U200D - B/W Dot-matrix Printer Technical Manual page 62

CPU pin functions
Pin CPU
No. Function
70 P46
71 P47
72 P48
73 P51/T04
74 P52
75 VCC
76 P53
77 P54
78 VSS
79 P55
80 P56
ROM (512K bit)
The printer control program and the character generator data are written in ROM (U8). The
control program controls the basic operations of the printer. All CPU (U5) operations follow this
program.
RAM (CPU internal 16K bit)
RAM is used as temporary storage for the following:
Data received from the interface (receive buffer)
Pattern data to be printed by the print head (printer buffer)
Data used by the CPU (U5) during processing (flags, pointers, etc.).
Rev. B
Signal Name I/O Level
HEAD2 O TTL
HEAD1 O TTL
HEAD9 O TTL
+24VCOM SW O TTL
CRCOM SW O TTL
VCC I (+5V)
PFCOM SW O TTL
CLK REQ O TTL
VSS I (0V)
RTS O TTL
PLED/DSW0 I/O TTL
TM-U200D/U200PD Technical Manual
Description
Print head #2 drive signal Low: on
Print head #1 drive signal Low: on
Print head #9 drive signal Low: on
Head, auto cutter, Drawer kick-out power
switch Low: drive
Motor, carriage power switch Low: motor drive
Main power terminal (+5V)
Motor, paper feed power switch Low: motor
drive
HOST interface CLK REQ
GND terminal
Host interface RTS Low: on
PAPER OUT LED Low: on
DIP SW 2-2 read when P100 is low
Mechanism Configuration and Operating Principles