Rabbit RabbitCore RCM5400W, Руководство пользователя

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OEM User’s Manual 35
4.1.1 Memory I/O Interface
The Rabbit 5000 address lines (A0–A19) 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, and are also used by the
RCM5400W.
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 any reason, you must add the following line at the
beginning of your program.
#define PORTA_AUX_IO // required to enable auxiliary I/O bus
Selected pins on Parallel Ports D and E as specified in Table 2 may be used for input
capture, quadrature decoder, DMA, and pulse-width modulator purposes.
4.1.2 Other Inputs and Outputs
The SMODE and STATUS pins can be brought out to header J1 instead of the PE5, PE6,
and PE7 pin with the jumper settings described in Appendix A.5–this option is reserved
for future use.
/RESET_IN is normally associated with the programming port, but may be used as an
external input to reset the Rabbit 5000 microprocessor and the RCM5400W memory.
/RESET_OUT is an output from the reset circuitry that can be used to reset other
peripheral devices.