Introduction

 

This page describes the electronic hand-held instrument invented by mr. Voja Antonic. It's based on Microchip's PIC16F84 (running at 10 MHz) and a standard 2x20 character LCD-module.

 

The instrument is intended to be a digital laboratory tool for hardware and software debugging. The four functions are:

 

  Serial code receiver   The serial code receiver receives 42 bytes and displays them in both HEX and ASCII. The baud rate is selectale in 8 steps from 1200 to 115200. The data "word-length" is 7 or 8 bits with or without a parity bit. Signal polarity can be chosen to fit either a TTL signal or an RS-232 signal.

  Logic state analyzer   This is a one-channel logic state analyzer. It fetches 300 single bit samples in a selectable rate from 25ms to 1ÁS (40 Hz to 1 MHz in 16 steps). The sampling is trigged at at a selectable edge (high-to-low or low-to-high). The digital waveforms are displayed in a pseudographic mode on the LCD.

  Frequency counter   The frequency counter displays the frequency with up to 8 digits on the LCD. The refresh rate is 500ms. There are four ranges, from 5 MHz to 40 MHz, which affect the count resolution (from 4 to 32).

  Logic probe   The low and high logic levels are displayed by LEDs which are OFF if the probe tip is floating. A transition (high-to-low or low-to-high) is indicated by turning on the "pulse" -LED for 80ms.

 

There is also a battery manager menu to control the charge / discharge of the built-in rechargable battery which consists of four AAA cells (= LR03 or R03).

 

The user interface is with LED and LCD output and command input by two keys. Signal input can be either TTL levels or RS-232 levels.

 

Microchip Technology Inc. has also published this project as an application note called
"
Engineer's Assistant Using a PIC16F84A", AN689. This is the original project description on which these web-pages are based. You should read this document to get all the details.

 

Good luck with your assistant !

 

Erik Grindheim, 06.04.2000