User`s manual

OP710038


 Hardware
J8
GND
CTS/RX1
RTS/TX1
RX0
GND
RTS/TX1
CTS/RX1
J10
TX0
1
2
3
4
5
6
7
8
9
10
246
8
13579
RS-232 Communication
Figure 3-17 shows the RS-232 signals on header J8 and header J10 (the
DE-9 connector).
Figure 3-17. RS-232 Signals
Pin 9 on header J10, the DE-9 connector, may be configured to
carry DCIN, the input voltage, by adding a 0 Ω resistor at R32.
Be careful when connecting other devices to header J10 when
R32 is installed since not all devices can handle DCIN. For
example, PCs are limited to 12 V.
The availability of DCIN on pin 9 of header J7 allows a DC
power supply to be made available to the device being
connected to the OP7100.
Rabbit Semiconductor has RS-232 support libraries for Z180 Ports 0 and
1. The following functional support for serial communication is included.
• Initializing the serial ports.
• Monitoring and reading a circular receive buffer.
• Monitoring and writing to a circular transmit buffer.
• CTS (clear to send) and RTS (request to send) control for Z180 Port 0.
Receive and Transmit Buffers
Serial communication is easier with a background interrupt routine that
updates receive and transmit buffers. Every time a port receives a charac-
ter, the interrupt routine places it into the receive buffer. A program can
read the data one character at a time or as a string of characters terminated
by a special character.