RS232 serial orders converter

Microcontroller based serial orders converter

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Role

Sole SW designer and HW consultor on a high reliability serial data parser/detector device which controls the radio FM emergency broadcast system. 150 in service on national broadcasts since May 2013, 0 defects.

Purpose

Developed as an ad-hoc, high reliability, non-expensive substitute for controlling the change to and from advertisement time and broadcast system in live FM radio broadcasts.
Made for a Spanish national radio network (Cadena COPE, 3rd on audience ratings, first emission in 1979).

This device is placed in every emitter centre. It receives a serial RS232 frame (from a satellite receptor, or DSL line), parses it, extracts the associated command in that frame and commutes the relays to carry out that command. It controls:

  • forced interruption to emergency broadcast channel
  • change from regional/national emission to advertisement and vice-versa
  • change between different radio programmes

Features

  • "no maintenance" electronic design, made to last years:
    • Tantalum based capacitors (which don't dry)
    • no SMPS (with capacitors that will dry)
    • Oversized transformer cold power source
  • Microcontroller based
  • TDD driven software development
  • in & out RS232 for receiving and daisy chaining, relay's connections on parallel port
  • informative LEDs that output the current state or signal errors in the frame

Deployment

150 currently in service since May 2013. 0 returns/defects. Tested by client in-situ (on national broadcasts).

Technologies used

C, Microcontrollers, Test Driven Development