Technical data

Host interface 22/72

netRAPID Chip Carrier | Design Guide

Activating the serial dual-port memory mode (SPI)

A low signal at DPM_DIRQn activates the SPI mode (via a 2.2 k pull-down resistor).

netRAPID internal pull-up and pull-down resistors

Pin Signal netX 10 on NRP 10 netX 52 on NRP 52

DPM_DIRQn

50 k pull-up 50 k pull-up

DPM_SIRQn

50 k pull-up 50 k pull-down

Important: Never drive the host interface mode signal (DPM_DIRQn pin 39). Instead,

operation with pull-down and pull-up resistors is recommended.

4.3 Parallel dual-port memory

The communication for all input and output data and control commands between the netRAPID

and the host system are exchanged over the dual port memory.

From host system side, the dual-port memory looks like static RAM. The netRAPID always

provides addressing capabilities for 16 KByte dual port memory. Only a few signals are used to

control the access to the dual port memory.

These data lines can drive 6 mA at maximum.

To avoid data loss by simultaneous access at the same memory cell, it is necessary to use the

BUSYn signal.

Please refer to the special documents for the basic description of the data model and

communication methods with devices based on the netX.

4.3.1 Address bus and data bus

These signal lines contain the address bus lines A0 up to A13 and data bus lines D0 up to D15 of

the dual-port memory. The address and data lines are non-multiplexed. The dual-port memory of

the netRAPID has a size of 16 KB. NRP 10 devices only use the lowest 8 KB of the dual-port

memory.

Unused address lines may be equipped with a pull-down resistor of 560 .

The following table explains the available possibilities:

netRAPID Host address space Connect Pull-down to address line

NRP 10 8 KB A0 ... A12 A13

NRP 52 16 KB A0 ... A13 none

Table 6: Possibilities for usage of dual-port memory

The netRAPID supports additional data bus lines to drive a 16 bit data interface.

 If your host interface can support a width of 16-bit, connect the DPM_SIRQn signal to V

 If not, let the DPM_SIRQn signal unconnected causing 16-bit devices to work in 8-bit mode.