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Datasheet of 20-101-1194 - MODULE RABBITCORE RCM3309 ROHS
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User’s Manual
27
4.1.1 Memory I/O Interface
The Rabbit 3000 address lines (A0–A18) and all the data lines (D0–D7) are routed
internally to the onboard flash memory and SRAM chips. I/O write (/IOWR) and I/O read
(/IORD) are available for interfacing to external devices.
Parallel Port A can also be used as an external I/O data bus to isolate external I/O from the
main data bus. Parallel Port B pins PB2–PB5 and PB7 can also be used as an auxiliary
address bus.
When using the auxiliary I/O bus for a digital output or the LCD/keypad module on the
Prototyping Board, or for any other reason, you must add the following line at the begin-
ning of your program.
#define PORTA_AUX_IO
// required to enable auxiliary I/O bus
4.1.2 LEDs
The RCM3309/RCM3319 has three Ethernet status LEDs located beside the RJ-45
Ethernet jack—these are discussed in Section 4.2.
Addiitionally, there is one dual LED DS4. PD1 on the Rabbit 3000’s Parallel Port D is
used to enable the serial flash, and is connected to the green
CE
LED at DS4, which blinks
when data are being written to or read from the serial flash. The red
BSY
LED at DS4 is a
user-programmable LED, and is controlled by PD0. The
CONTROLLED.C
and
FLASHLED.C
sample programs in the Dynamic C
SAMPLES\RCM3300
folder show how to set up and
use this user-programmable LED.
4.1.3 Other Inputs and Outputs
The status, /RESET_IN, SMODE0, and SMODE1 I/O are normally associated with the
programming port. Since the status pin is not used by the system once a program has been
downloaded and is running, the status pin can then be used as a general-purpose CMOS
output. The programming port is described in more detail in Section 4.2.3.
/RES is an output from the reset circuitry that can be used to reset external peripheral
devices.
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