Christoph's - Atmel

Atmel's AVR series of multi-purpose microcontrollers

One of the easiest-to-use microcontrollers out there, the Atmel AVR AT90S8515 microcontroller's only downside is its price.


Programming the micro

To program the microcontroller I used its ISP interface instead of buying one of these expensive programming kits. For instructions on how to program the micro using the atmel's SPI bus, refer to the Atmel Datasheet available from the atmel homepage - or download aVrite from the Dontronics homepage. To use aVrite, wire the micro to your PC's parallel port as follows:

PC-to-uC ASCII Art
LPT               micro
2,6,7,8,9 --->|-- VCC   (5 low-loss schottkys)
        3 ------- reset        
        4 ------- SCK
        5 ------- MOSI
       10 --###-- MISO  (1K resistor)
LPT Connector

Generating ASM code

The lazy person I am, I decided not to write Assembler myself but let a compiler do this job. I chose AVRgcc, available from the Dontronics homepage - mainly because it's free, fast and much easier to use than comercially available compilers.

Wiring the micro

This is the fun part. Basically you just have to supply +5V to VCC, hook GND to 0V and connect a resonator (I chose 4MHz) to XTAL1, XTAL2 and GND (the latter to the center pin of the resonator).
You are ready to begin experimenting with your micro.

This is my wiring diagram. It was originally not intended to be on my homepage, so resistors are shown as pink lines, red lines are "holes".

Thumbnail of PCB Layout
Thumbnail of PCB Layout (zoomable)

The circuit on the top (far-)left is kind of an ultrasonic meter. The one to the top left of the micro is the ISP interface and the reset pin. The one to the bottom left is a LCD interface, with a contrast poti. To the bottom of the micro is the resonator socket. Below this socket are two transistors I used as amplifiers for sensors.