MCU-based alarm reference design -

MCU-based alarm reference design

An alarm control panel reference design from Motorola Semiconductor Products Sector (SPS) is to ease design based on HCS12 microcontrollers.

It describes how to set up and use features on the MC9S12DP256 flash microcontroller (MCU), such as flash memory, phase locked loop, interrupts, serial communications interface, serial peripheral interface and analog to digital converter. It demonstrates how to connect to a sensor node, PC, input and output devices, connect to sensing alarm lines, generate sound and flashing LEDs (light emitting diodes), sense a rotary encoder, store configuration data, and drive a liquid crystal display.

Based on Motorola's MC9S12DP256 flash MCU, the reference design was developed by Motorola and Elektronikladen Mickrocomputer (Detmold, Germany), a member of Motorola's Semiconductor Products Sector's Design Alliance Program.

The alarm control panel reference design is available in a modular fashion such that the hardware modules in the tool can be re-used for other HCS12 derivatives and other applications.

There are three alarm line inputs that may be used to connect industrial standard alarm contacts. The alarm lines are designed to recognise external manipulations, such as attempts to cut the wires or shorten a line. The reference design is also engineered to enable connection to several sensors and nodes in a home using a LIN (Local Interconnect Network) bus.

Pre-built hardware for the Networked Alarm Control Panel is available from Elektronikladen Mikrocomputer (

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