Copyright © 2015 Robot Circuits, LLC
33
RCAT-1A Rev A3 Designer’s manual
Serious Power for the Serious Designer
Referring to Figure 33:
Figure 33
First, assuming all other things equal, the green signal path shows how you can route J6 pin 1 signal through
translator U8 in similar fashion to the previous USARTS by installing shunts on jumper JP6 across pins B-C and on
jumper JP15 across pins A-B.
Likewise the violet signal path shows how you can J6 pin 2 through translator U9 by installing shunts on jumper
JP7 across pins B-C and on jumper JP17 across pins A-B.
Unlike the USARTS 2 and 3, the isolation jumper, JP20 is handled differently than jumpers JP21 and JP22 are in
the other cases.
Also, please notice that U8 pin 7 connects directly to CPU port PD3. This is different from the other USARTS as
well.
These differences are due to the fact that USART 1 is shared between J6 and J10. See the portion of Figure 33
showing J10 near the bottom? J10 is intended for direct connection to a Netburner™ Serial to Ethernet
converter.
If J10 is not being used, then you will have no issues. If J10 IS being used, then you must make sure you do not
also bring conflicting signals into J6.
By paying attention to the schematics you should be able to navigate this arrangement with no problems.
