Analog Features; Serial Communication - Rabbit RabbitCore RCM5400W User Manual

B.4.3 Analog Features
The Prototyping Board has typical support circuitry installed to complement the ADS7870
A/D converter chip, which is available on other RabbitCore modules, but is not installed on
the RCM5400W. Since the RCM5400W RabbitCore module does not have the ADS7870
A/D converter chip, the Prototyping Board will not provide A/D converter capability with
the RCM5400W RabbitCore module.
B.4.4 Serial Communication
The Prototyping Board allows you to access the serial ports from the RCM5400W module.
Table B-3 summarizes the configuration options.
Table B-3. Prototyping Board Serial Port Configurations
Serial Port
A
B
C
D
E
F
Serial Ports E and F may be used as serial ports, or the corresponding pins at header loca-
tion J2 may be used as parallel ports.
B.4.4.1 RS-232
RS-232 serial communication on header J4 on both Prototyping Boards is supported by an
RS-232 transceiver installed at U3. This transceiver provides the voltage output, slew rate,
and input voltage immunity required to meet the RS-232 serial communication protocol.
Basically, the chip translates the Rabbit 5000's signals to RS-232 signal levels. Note that
the polarity is reversed in an RS-232 circuit so that a +3.3 V output becomes approxi-
mately -10 V and 0 V is output as +10 V. The RS-232 transceiver also provides the proper
line loading for reliable communication.
RS-232 can be used effectively at the RCM5400W module's maximum baud rate for dis-
tances of up to 15 m.
100
Header Default Use
J2 Programming Port
J2 Serial Flash
J2, J4
J2, J4
J2
J2
Alternate Use
RS-232
RS-232
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RabbitCore RCM5400W
RS-232
RS-232
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