Architecture of a Typical Microcontroller

Microcontrollers are the building blocks of any digital signal processing system. In layman’s terms, they can be described as miniature computers that are present on chips. They consume very little amount of power and are self sufficient. They are similar to microprocessors but contain some additional elements such as read only memory in the form of EEPROM (Electrical Programmable Read Only Memory) and a read write memory that usually utilises flash technology. Another difference between microcontrollers and microprocessors is the clock speed. Microcontrollers usually operate at low clock speeds. Low clock speeds are adopted as they are suitable for the operations that are usually performed using microcontrollers. Also, this ensures that they consume less power.

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About Digital Signal Processing

Today, signals, i.e., quantities that fluctuate over time with high frequency, have acquired a great amount of importance and are being used in many fields, especially communication. Digital signal processing involves converting digital data into signals, making its transfer easier and subsequently converting these signals back into the original form. A signal has many characteristics or domains such as time domain, spatial domain, frequency, wavelet domain, etc. Anyone among these can be used to process a respective signal. From among these, the engineer usually selects the one that best represents the characteristics of the signal concerned or, in other words, the one from which data can be obtained easily. To ascertain the required characteristic, the engineer may try out many among these properties. The use of signals has gone up especially with the use of computers. Computers can analyze and process only digital (discrete) data and cannot handle analog (continuous) data. Thus, conversion of the signal from analog to the digital form becomes necessary. The digital signal is exactly similar to the analog signal that it has been obtained from; some mathematical techniques such as the Nyquist-Shannon sampling theorem are used. Usually, after analysis or transformation, the output signal is…

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AVR DDS signal generator V2.0

Finally, the second version of the improved AVR DDS signal generator is here. THE first AVR DDS V1.0 generator was only an attempt to run the DDS algorithm without any analog amplitude control. In this DDS generator version, I still wanted to keep things as simple as possible using a minimum count of widely available components in the updated circuit. Also, I kept a single-sided PCB approach. AVR DDS specification AVR DDS signal generator V2.0 is a firmware-based DDS signal generator that uses a slightly modified Jesper’s mini DDS algorithm adapted to AVR-GCC C code as in-line ASM. The AVR DDS signal generator has two outputs – one for DDS signal and another for high speed [1, 8MHz] square signal – which may be used to bring back to life microcontrollers with wrong fuse settings for other purposes where a high-speed square signal may be needed. A high-speed (HS) signal is output directly from the Atmega16 OC1A(PD5) pin. The DDS output is used for all complex signals generated via the R2R resistor network and is adjusted via LM358N offset and amplitude regulating circuits. Two potentiometers can control offset and amplitude. The offset can be controlled in range +5V..-5V while magnitude…

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