Design Overview; Description - Sony Ericsson RS232 interface for GT47 embedded apps UART Application Note

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RS232 interface for GT47 embedded apps UART

2 Design Overview

The RS232 Level Translator PCB Assembly consists of a PCB and plastic

back shell or 'hood' compatible with 9-pin 'D' sub-miniature RS232

connectors (DB9).

It has been designed to provide a compatible termination to the 15-way

cable assembly provided as part of the GT47 Developer's kit. The 15-way

cable assembly has a 15 pin high density sub-miniature 'D' connector

(HD15) at one end which connects to the GT47. At the other end of the

cable the 15 connections are split between a DB9 socket and 7 flying

leads (GND is common to both).

Down the edge of the RS232 PCB, solder terminals T1-T7 are designed to

accept the seven flying leads of the GT47 accessory cable. The other end

of the PCB has a DB9 socket with a DCE pin out. The RS232 PCB uses a

DCE pin out so it can be connected directly to a PC Com Port (DTE) using

a 9-way straight-through modem cable. If the GT47 needs to communicate

with another DCE device use a "Null-Modem" cable between devices.

For a typical assembly, solder each of the 7 flying leads onto the 7 solder

terminals of the level shifter PCB. When not used as part of the RS232

connection scheme, solder terminals T4, T6 and T7 still provide a suitable

anchor point for the flying leads. The second hole for each solder terminal

may be used for extending the wiring by soldering a new length of cable in

series with the original.

Configuration of the design can be either the default, simple 3-wire

interface (RD, TD, GND), or a 5-wire interface (RD, TD, RTS, CTS, GND)

with the addition of two surface mount resistors.

The connections incorporated onto the PCB are listed in table 1.

LZT 123 7698 R1B

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