Various Detector Circuits - Epson TM-U200 series Technical Manual

C o n fid e n tia l
RAM (CPU internal 2K 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.).
Operation panel
The operation panel is located on the main circuit board and has 3 LEDs (POWER, ERROR, and
PAPER OUT) and 1 switch (FEED). The POWER LED is driven at the same time as +5 V is
supplied by the power supply circuit. The ERROR and PAPER OUT LEDs are driven by U5.
Switch detection is also executed by the U5.
U5
32 PF SW
P82
1 ELED/DSW9
P57/T03
80 PLED/DSW0
P56/INT3/TI2

Various detector circuits

When the printer detects paper, the paper detector at the paper inlet turns the input signal to the
CPU (U5) LOW. This detector also functions as the semi-automatic loading detector.
A home position sensor is provided to detect the print head position. The input signal to the
CPU (U5) becomes LOW when home position is detected.
Rev. A
+5V
Q35
R54
1 (POWER)
D13
2
Figure 2-21 Operation panel circuit
Mechanism Configuration and Operating Principles 2-21
TM-U200 Series (Type B) Technical Manual
Q36
R55 R56
1 (PAPER) 1 (ERROR)
D12 D11
2 2
R41
R15
GND
SW2
C17