Clock configuration on the ATxmega32A4U is not just a matter of writing a source-select field: the clock registers can be locked, and the documented CCP window allows only four instruction cycles between signature and data write.
Abstract: I recently stumbled across an interesting fact in the datasheet for the ATMEGA32u4, the microcontroller I am using for my Einstepper Project. I was surprised to find that Atmel had included a temperature sensor in the core of the device that you can read using the internal ADC. As it turns out, there are
ATMEGA Core Temperature Sensor Read More »
Introduction The main incentive behind this project was to see how much I could cram, in terms of both hardware and software, into a wristwatch-like device that is no larger than the display itself. An OLED display was chosen for being only 1.5mm thick and not requiring a backlight (each pixel produces its own light),
DIY Digital Wristwatch Read More »
A technical walkthrough of an LM335-to-ATmega8 temperature channel: the correct kelvin-to-celsius arithmetic, ideal 10-bit code scaling, and the offset, reference and amplifier limits that decide real accuracy.
Reading an LM335 with an ATmega8 ADC: Resolution, Reference and LM324 Limits Read More »
A character-by-character parser design for the XX@HH:MM# keypad protocol, with corrected 00..23 hour validation, a bounded nine-byte buffer, and explicit clear, error and execute transitions. Design analysis only; no firmware was built or tested.
Validating Keypad Commands with a State Machine: the XX@HH:MM# Protocol Read More »
As part of my 3D printer project, one of the big electronics hurdles to overcome was a motor controller for a BLDC (BrushLess Direct Current) motor. Searching for a cheap, off the shelf controllers that would interface easily with a microcontroller turned up fruitless, so I took the opportunity to design my own circuit. It was
BLDC motor control using Atmega328 Read More »
ADC timing sets the ceiling before you write any code The ATmega2560’s 10-bit successive-approximation ADC runs from its own clock domain, divided from the system clock by ADPS2:0 in ADCSRA. The datasheet allows 50–200 kHz of ADC clock for full resolution, spends 13 cycles on a normal conversion and 25 on the first after ADEN,
Semiconductor curve tracers were frequently used in analog circuit designs many decades ago, at a time when discrete semiconductor devices were in dominance and ICs were scarce. While curve tracers are no longer widely used nowadays due to the ubiquity of digital circuitry and computer aided designs, they are still quite popular in the educational
Yet Another Semiconductor V/I Curve Tracer – I Read More »
I’m planning to build a EEVblog-ish constant dummy load for battery and power supply testing. Dave in his build used a LCD voltmeter for the display. In the senseless pursuit of difference, I tried other display solutions including character LCD, graphics LCD, OLED, TFT, AMOLED, IPS, which resulted in several previous blogs but nothing ends up
Hacking a cheap LED voltmeter Read More »
Seven segment LED displays are known to be resource and power hungry. But because they are visually so charming and readable from a far viewing distance and at a much wider viewing angle as compared to any other electronic displays, they are still hugely popular. The required number of I/O pins to drive the LED
High-voltage seven segment LED display driver with SPI interface Read More »
