User`s manual

User’s Manual 17
• Watchdog support routines. Although the Rabbit watchdog can be disabled, this is not
recommended since the watchdog is an essential facility for recovering when a program
stops running. Very few systems are crash-free in real life.
3.1.2 Using Dynamic C
You have a choice of doing your software development in the flash memory or in the static
RAM. There are 256K bytes of flash and 128K SRAM memory. The advantage of work-
ing in RAM is to save wear on the flash, which is limited to about 100,000 writes.
Note that an application can be developed in RAM, but cannot run standalone from
RAM after the programming cable is disconnected. All applications can only run from
flash.
Do not depend on the flash sector size for debugging. Due to the volatility of the flash
market, the RabbitCore 2000 and Dynamic C were designed to accommodate flash
devices with various sector sizes.
When using flash EPROM, the compile to a file is followed by a download to the flash
EPROM. The disadvantage of using flash EPROM is that interrupts must be disabled for
approximately 5 ms whenever a break point is set in the program. This can crash fast
interrupt routines that are running while you stop at a break point or single-step the pro-
gram. Flash EPROM or RAM is selected with the Dynamic C Options > Compiler
menu.
3.2 I/O
The RabbitCore 2000 was designed to interface with other systems, and so there are no
drivers written specifically for this purpose. The general Dynamic C read and write func-
tions allow you to customize the parallel I/O to meet your specific needs. For example,
use
WrPortI(PEDDR, &PEDDRShadow, 0x00);
to set all the port E bits as inputs, or use
WrPortI(PEDDR, &PEDDRShadow, 0xFF);
to set all the port E bits as outputs.
The sample programs in the Dynamic C SAMPLES directory provide further examples.
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