Digi RCM4000 - Manual (Page 38)

32 RabbitCore RCM4000
4.2.3 Programming Port
The RCM4000 is programmed via the 10-pin header labeled J1. The programming port
uses the Rabbit 4000’s Serial Port A for communication. Dynamic C uses the programming
port to download and debug programs.
Serial Port A is also used for the following operations.
• Cold-boot the Rabbit 4000 on the RCM4000 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 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 I/O pin
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 4000 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 4000 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 output once a program has been downloaded and
is running.
The reset pin is an external input that is used to reset the Rabbit 4000.
Refer to the Rabbit 4000 Microprocessor User’s Manual for more information.