Citizen CL-S400DT - RS232 C I;F Circuit; USB I;F Control Circuit

Chapter 2 Operating Principles
2-2. Operation of Control Parts
CL-S400DT 2-26
(5) USB I/F control circuit
The USB I/F control circuit interfaces with the USB (Universal Serial Bus).
NAND gates (U22A, U22B and U22C) and transistor Q25 consist of a USB connection
detecting circuit. When USB connector is connected to the printer, pin 1 (USBVCC) of J16 is
set to “High”. The detection circuit detects this level and outputs a UBINTP pulse to the CPU to
inform of the USB connection.
(6) RS232C I/F circuit
The RS232C I/F circuit consists of U21 and U22 (receiver/transmitter) and receives and
transmits the RS232C I/F signals.
1
2
3
4
5
R129
J16
R135
Q25
DTA114EM
C133
R134
UBINTP
UDP
UDM
SG
USBVCC
USBLGND
DP
DM
USB I/F
R132
5
6
4
9
8
10
1
3
2
+3.3V
+3.3V
U1A
CPU
USBON
P76
172
D23
121
160
161
UDP
UDM
R136
U22C
U22A
U22B
[SA Main PCB]
R130
R131
R133
USB connection detecting circuit
"High" when USB
connector is connected.
13
15
12
10
Vcc
T1IN
T2IN
R1OUT
R2OUT
U21
Receiver/Transmitter
2
20
3
6
J15
8
17
16
9
TXD1
DTR1
RXD1
DSR1
19
+3.3V
[SA Main PCB]
ICL3222EIVZ
20
nRESET
SHDN
To/From
U1A
CPU
4
5
25
T1OUT
T2OUT
R1IN
R2IN
13
15
12
10
Vcc
T1IN
T2IN
R1OUT
R2OUT
U23
8
17
16
9
RTS1
CTS1
RS_INIT
19
+3.3V
ICL3222EIVZ
20
nRESET
SHDN
T1OUT
T2OUT
R1IN
R2IN
TXD
DTR
RXD
DSR
RTS
CTS
INIT
RS232C I/F
Receiver/Transmitter