Usb I/F Control Circuit; Rs232C I/F Circuit - Citizen CL-S400DT Technical Manual

Chapter 2 Operating Principles
2-2. Operation of Control Parts

(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.
U1A
CPU
172
USBON
P76
121
UBINTP
D23
161
UDM
UDM
160
UDP
UDP

(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.
TXD1
DTR1
RXD1
DSR1
nRESET
To/From
U1A
CPU
RTS1
CTS1
RS_INIT
nRESET
CL-S400DT
USB connection detecting circuit
+3.3V
R136
U22C
9
8
10
U21
+3.3V
Receiver/Transmitter
19
Vcc
13
T1IN T1OUT
12
T2OUT
T2IN
15
R1OUT R1IN
10
R2OUT R2IN
20
SHDN
ICL3222EIVZ
U23
+3.3V
Receiver/Transmitter
19
Vcc
13
T1IN T1OUT
12
T2OUT
T2IN
15
R1IN
R1OUT
10
R2OUT R2IN
20
SHDN
ICL3222EIVZ
+3.3V
Q25
DTA114EM
U22A
1
3
2
R129
5
6
4
U22B
C133
2
17 TXD
8 DTR
16
RXD
9 DSR
RTS
CTS
INIT
17
8
16
9
[SA Main PCB]
2-26
"High" when USB
connector is connected.
R132
R134
R135
USBVCC
R130
DM
R131
DP
R133
USBLGND
SG
[SA Main PCB]
J15
20
3
RS232C I/F
6
4
5
25
J16
1
2
3
USB I/F
4
5