User’s Manual
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The programming port may also be used as a serial port via the DIAG connector on the
programming cable.
In addition to Serial Port A, the Rabbit 3000 startup-mode (SMODE0, SMODE1), status,
and reset pins are available on the programming port.
The two startup mode pins determine what happens after a reset—the Rabbit 3000 is
either cold-booted or the program begins executing at address 0x0000.
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 CMOS output.
The reset pin is an external input that is used to reset the Rabbit 3000.
Refer to the Rabbit 3000 Microprocessor User’s Manual for more information.