Memory I/O Interface; Other Inputs And Outputs - Rabbit RabbitCore RCM4100 User Manual

Table 2. RCM4100 Series Pinout Configurations (continued)
Pin Pin Name
40–47 LN[0:7]
48 CONVERT/n.c. Digital Input
49 VREF/n.c.
50 GND

4.1.1 Memory I/O Interface

The Rabbit 4000 address lines (A0–A19) and all the data lines (D0–D7) are routed inter-
nally to the onboard flash memory and SRAM chips. I/0 write (/IOWR) and I/0 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–PB7 can also be used as an auxiliary address bus.
When using the auxiliary I/O bus for any reason, you must add the following line at the
beginning of your program.
#define PORTA_AUX_IO
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 status and the two SMODE pins, SMODE0 and SMODE1, can be brought out to
header J2 instead of PE5–PE7 as explained in Appendix A.5.
/RESET_IN is normally associated with the programming port, but may be used as an
external input to reset the Rabbit 4000 microprocessor and the module memory.
/RESET_OUT is an output from the reset circuitry that can be used to reset other
peripheral devices.
32
Default Use
Analog Input
Analog reference
voltage
Ground
// required to enable auxiliary I/O bus
Alternate Use
A/D converter
(RCM4100 only)
1.15 V/2.048 V/2.500 V
on-chip ref. voltage
(RCM4100 only)
Notes
RabbitCore RCM4100