101-1226 Rabbit Semiconductor, 101-1226 Datasheet - Page 32

• Manufacturer Part Number: 101-1226
• Description: RCM3900 DEV KIT UNIVERSAL
• Manufacturer: Rabbit Semiconductor
• Series: RabbitCore 3900r
• Type: MPU Moduler

Specifications of 101-1226

• Contents: RabbitCore Module, Dev. Board, AC Adapter, Cable and Dynamic C® CD-Rom
• For Use With/related Products: RCM3900
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 316-1137

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—pay attention to the loading on
these two signals if you use them since these signals are also used by the RCM3900.
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–PB7 can also be used as an auxiliary address bus.
When using the external 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 RCM3900 has three Ethernet status LEDs located beside the RJ-45 Ethernet jack—
these are discussed in Section 4.2.2.
Additionally, there is one dual LED DS4. PD1 on the Rabbit 3000’s Parallel Port D is used
to enable the NAND flash on the RCM3900 model, but is connected to the green CE LED
at DS4, which is not used. The red BSY LED at DS4 is a user-programmable LED, and is
controlled by PD0. The
and
sample programs in the
CONTROLLEDS.C
FLASHLEDS.C
Dynamic C
folder show how to set up and use this user-
SAMPLES\RCM3900
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.
/RESET_IN is an external input used to reset the Rabbit 3000 microprocessor and the
RCM3900 onboard peripheral circuits. /RES is an output from the reset circuitry that can
be used to reset external peripheral devices.
RabbitCore RCM3900 User’s Manual
32