User’s Manual
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4.3.2 Programming Port
The RCM2000 has a 10-pin program header labeled J3. The programming port uses the
Rabbit 2000’s Serial Port A for communication. Dynamic C uses the programming port to
download and debug programs.
The programming port is also used for the following operations.
Cold-boot the Rabbit 2000 after a reset.
Remotely download and debug a program over an Ethernet connection using the
RabbitLink EG2110.
Fast copy designated portions of flash memory from one Rabbit-based board (the
master) to another (the slave) using the Rabbit Cloning Board.
Alternate Uses of the Serial Programming Port
All three clocked Serial Port A signals are available as
a synchronous serial port
an asynchronous serial port, with the clock line usable as a general CMOS input
The serial programming port may also be used as a serial port via the DIAG connector on
the serial programming cable.
In addition to Serial Port A, the Rabbit 2000 startup-mode (SMODE0, SMODE1), status,
and reset pins are available on the serial programming port.
The two startup mode pins determine what happens after a reset—the Rabbit 2000 is
either cold-booted or the program begins executing at address 0x0000. These two
SMODE pins can be used as general inputs once the cold boot is complete.
The status pin is used by Dynamic C to determine whether a Rabbit microprocessor is
present. The status output has three different programmable functions:
1. It can be driven low on the first op code fetch cycle.
2. It can be driven low during an interrupt acknowledge cycle.
3. It can also serve as a general-purpose output.
The /RESET_IN pin is an external input that is used to reset the Rabbit 2000 and the
onboard peripheral circuits on the RabbitCore module. The serial programming port can be
used to force a hard reset on the RabbitCore module by asserting the /RESET_IN signal.
Refer to the Rabbit 2000 Microprocessor User’s Manual for more information.