General Purpose Port (Port 1,2) - Hitachi HIDIC MICRO-EH Applications Manual

(2) 1:n station communication on RS-485
When station number mode is used on RS-485, termination command (NAK FF) from host/PC can conflict with reply
from CPU, and CPU can fail to receive this command. Pay attention to this possibility at using this command.
(3) Port 2 hardware
The circuit diagram of port 2 and the signal list are shown in Figure 11.4 and Table 11.6 respectively.
Pin No. Signal
abbreviation
1] NC
2] NC
3] NC
4] NC
5] Vcc
6] RSN
7] SG
8] CSP
9] RT
10] RDN
11] RDP
12] SDN
13] SDP
14] RSP
15] CSN

11.4 General purpose port (Port 1,2)

General purpose port can be configured either port 1 or port 2 by FUN 5 command in user program. General purpose port
enables serial communication to devices like bar code reader by TRNS/RECV command in user program.
Even if configured, the port works as general purpose port only CPU is in RUN status. Port is changed back to dedicated
port when CPU is in STOP status.
* General purpose port is supported by software version 1.30 (WRF051=H0130) or newer.
General purpose port
7] SG
5] VCC
VCC
14] RSP
RS2
6] RSN
15] CSN
CS2
8] CSP
13] SDP
TX2
12] SDN
10] RDN
RX2
11] RDP
9] RT
Figure 11.4 Circuit diagram and pin numbers for port 2
Table 11.6 List of port 2 signals
Direction
CPU Host
Not used
Not used
Not used
Not used
5 V DC is supplied.
Transmission request signal. When it is high low, CPU is ready to receive data..
Signal ground
Receive enabled signal. When it is high, connected device is ready to receive data.
Terminating resistor (120Ω). Connect to pin 10 if necessary.
Data received by the CPU -
Data received by the CPU +
Data sent by the CPU -
Data sent by the CPU +
Transmission request signal. When it is high level, CPU is ready to receive data.
Receive enabled signal. When it is low, connected device is ready to receive data.
CPU in STOP
Dedicated port
Chapter 11 Communication Specifications
8]
15]
7]
14]
6]
13]
5]
12]
4]
11]
3]
10]
2]
9]
1]
Meaning
Switching
automatically
General purpose port
11-4
CPU in RUN