Super Easy AVR Assembly Programming

From this May on, I somehow got interested again in assembly language. It's been more than 25 years since my last assembly programming, during and a bit after my university years. I've been playing around with the Atmel’s microcontrollers for some time now, so I thought I would better try something with them. A simple Attiny13 blinker for instance ... My previous experience on assembly language, apart from being ages old, also concerned (as might expected) an ancient chip ... the 6502 microprocessor. Who really knows about it know? ...

Smart Battery charger

Smart Battery charger with ATtiny13 

Constant current charger for rechargable batteries and trickle charger for Alkalines.

After a lot of experimentation this is an improved design of the alkaline battery trickle charger presented in a previous post. The new design charges alkaline batteries with fixed peak, variable duty cycle current pulses and automatic shut down. In addition, one charging mode can be used to charge NiMh or NiCd batteries with constant current. Actually, I was somewhat disappointed from the alkaline batteries charging results (lots of leaking), so I though that I should find a better use for my hardware.

This is the schematic of the improved charger.

Apart from the code the difference from the previous circuit comes from the way the T1, T2 transistors are placed. Once T1 is turned on by the μC it provides current (around 10mA) to the LED1. Voltage drop on this LED is constant and depends on its color. (1.6V for RED diode, 1.9V for green, 3V for white).