User`s manual

Ewave Stamper User’s Manual V1.0

In the sections which follow, please refer to the pin-out diagram below of the STAMPER modem’s DB9

connector. The pin-out and pin-functions are identical on both the “Base” and “Mobile” versions of the

STAMPER modem.

6.4 Electrical Connection between BASIC Stamp and PC

This section describes how to electrically connect the STAMPER modem to the BASIC Stamp’s general-

purpose I/O pins to allow use of PBASIC’s SERIN and SEROUT commands for serial data transfers. If

you are using the BASIC Stamp’s debug port for serial communication, please see Section Section 3

Installation for hook-up instructions.

If your application is communicating at 9600 baud and using standard RS232 signal levels then converting

your system to wireless is a simple matter of substituting the STAMPER modem pair for the existing serial

cable. The STAMPER’s 9 pin serial connector follows the standard pin-out of a device designed to be

hooked directly to a PC’s 9 pin serial port: Pin 5 is ground, the STAMPER receives RS232 serial level data

on pin 3, and it transmits RS232 serial level data on pin 2. When replacing a serial cable between a PC and

a BASIC Stamp with a STAMPER modem pair, it is usually necessary to use a gender changer and null

modem with the STAMPER hooked to the BASIC Stamp. The null modem swaps the Serial In and Serial

Output lines, pins 2 and 3, and the gender changer is necessary because both the BASIC Stamp and the

STAMPER have female connectors.

6.5 BASIC Stamp Software Considerations

The STAMPER modem performs all commonly needed wireless protocol processing which allows your

application to simply send and receive individual bytes of data, just as you would over a serial cable.

The STAMPER modem makes your wireless software easy by automatically and transparently performing

these low-level functions:

• automatic packetization means your application can send individual data bytes one at a time or in

groups, and the STAMPER will take care of organizing the data into “packets” for efficient wireless

transfer and minimal latency.

• transparent protection from data corruption via a 16-bit CRC and automatic retry/acknowledge. The

STAMPERs will detect that data was corrupted and automatically re-transmit it. This means your

application will only see the good data.

The standard PBASIC SERIN and SEROUT commands are used to send and receive data through the

STAMPER modem link, just as you would a serial cable.