Copyright © 2015 Robot Circuits, LLC
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RCAT-1A Rev A3 Designer’s manual
Serious Power for the Serious Designer
Primary I/O Connector
First we will discuss connector J5 which we call the Primary I/O connector.
On the schematic you may see:
Figure 24
This indicates that connector J5 is a 3-row connector with rows A, B, and C. These row designators map to the
board as shown above. J5 has been laid-out this way to allow easy connection to devices that require signal, Vcc,
and ground connections in a 3-pin format. Most robot servos, sonar distance devices and other such devices are
designed this way.
To the right of the J5 are labels GND, Vcc, SIG which identify the purpose of each row. So – row ‘A’ connects to
each relevant port on the CPU, while rows B and C are common connections to Vcc and GND respectively.
Above J5 are labels that show what port the SIG row of each position connects to.
Just under J5 are position labels which are meant for easy reference. For example, J5 Position21-A refers to the
connection to CPU port PL1.
JTAG Connector
Next in our discussion is connector J4 which serves as the JTAG connector as discussed in the JTAG section
earlier. If the JTAG functions are not required, then several of the pins on J4 are available for direct port
connection. Here is the schematic of that connector:
Figure 25
