Serial Programming Cable; Changing Between Program Mode And Run Mode - Rabbit RCM3000 User Manual

4.3 Serial Programming Cable

The programming cable is used to connect the serial programming port of the RCM3000
to a PC serial COM port. The programming cable converts the RS-232 voltage levels used
by the PC serial port to the CMOS voltage levels used by the Rabbit 3000.
When the PROG connector on the programming cable is connected to the RCM3000
serial programming port at header J3, programs can be downloaded and debugged over the
serial interface.
The DIAG connector of the programming cable may be used on header J3 of the RCM3000
with the RCM3000 operating in the Run Mode. This allows the programming port to be
used as a regular serial port.

4.3.1 Changing Between Program Mode and Run Mode

The RCM3000 is automatically in Program Mode when the PROG connector on the pro-
gramming cable is attached, and is automatically in Run Mode when no programming
cable is attached. When the Rabbit 3000 is reset, the operating mode is determined by the
status of the SMODE pins. When the programming cable's PROG connector is attached,
the SMODE pins are pulled high, placing the Rabbit 3000 in the Program Mode. When the
programming cable's connector is not attached, the SMODE pins are pulled low,
PROG
causing the Rabbit 3000 to operate in the Run Mode.
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