Communication interfaces
The Ethernet switch:
A 10/100 Ethernet 5 port switch interconnects
the different high level peripherals of the robot
forming an embedded LAN. Two ports are
necessarily taken by the access point and the
SC12 controller. One port is generally used by
the IP camera but can be made available
depending of the application. Finally, the two
last ports are free to add other peripherals if
needed, those working in a completely
transparent way and independently from the
robot.
The I²C bus:
The I²C bus interconnects the micro-controllers
in charge of the low level modules to the central
processor that acts as a bridge with the upper
levels of the robot architecture. The SC12
controller works always as the master and all
communications necessarily pass by it. Up to
127 devices can be connected and the maximum
clock frequency of the bus is of 30kHz. The I²C
is accessible on pin 5 (GND), 6(SCL) and
9(SDA) of the DSUB-9 connector located on the
LEFT of the robot. The address of the chip in
charge of the left wheels is 0xA2, the one of the
right wheels is 0xA4.
WARNING!
The DSUB-9 connector on the left of the
robot presenting on its pins both the I²C
and the RS232 interfaces, be careful when
wiring a connection cable to prevent to
connect those to unwanted tensions.
The RS232 ports:
Two RS232 ports (RX,TX and GND) are available. Port COM1 on the DSUB-9 connector of
the left, port COM2 on the DSUB-9 connector of the right. Both ports present a standard PC
signal, for peripherals using TTL an interface such as the MAX232 is needed.
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