SRAM Data memory and Stack Pointer

SRAM data memory:      The data memory is divided into 32 locations for register file, next 64 locations for standard I/O memory, 160 locations for extended I/O memory and the next 1024 (* 1K memory for atmega168) locations for internal data SRAM. (* Internal data memory varies for atmega48/88/168/328 as 512,1K,1K,2K respectively).    The data memory map of AVR is given in the figure. Register File:      A Register file is an array of registers in a CPU. This serves as the central architectural element of any AVR uC. Each register is implemented by using SRAM (static RAM) with dedicated...

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CPU Basics

     I was on hunting of resources on fundamentals of CPU. Energy exhausted. Everything  I found was incomplete, irrelevant. Yeah, Internet gives us clues to solve a puzzle. I think I almost solved it.      Consider any process has to be controlled. Who is to control? CPU is the controlling element of any process. This word appeared for the first time during 1960's in the Industries. In late 1960's microprocessor based CPU's came to rule the industries. The microprocessors require many external components for their operation. This increased the cost of project. So, the manufacturers came up with an idea of...

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Basics of Burning

     Making a micro-controller to work is not a simple one. It consists of different processes, namely coding, compiling, burning(device programming), on the software side. On the hardware side it consists of providing a clock, proper supply voltage(refer datasheet). These are the compulsory requirements for a micro-controller to work.        Coding and compiling can be easily understood, because there are many tutorials in the internet. Burning and last important step for operation of micro-controller. Burning is the process of writing the compiled program(hex data) into the program memory of micro-controller.        To understand how burning works it is necessary to understand the CPU basics.  Here is a simplified explanation...

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Monostable Multivibrator- Debouncing

What is de-bouncing? Consider a simple push button connected to 5V supply. When the push button is pressed and released the signal across the output terminal of the button and the ground is expected to be like a signal given below: But the actual signal looks like this: As we can see from the above figure, bouncing of signal occurs during the transient time when mechanical switches are used, due to their surface roughness. This bouncing of wave should be avoided for proper functioning of the circuit in which the switch is used. This is known as switch de-bouncing.  How is it done? As mentioned in the previous post Monostable Multivibrator-...

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Digital Voltmeter - Part II

Ramp Type DVM   The block diagram of the Ramp type ADC is given below. The principle and working of the Ramp type ADC is explained in a simplified manner in this post. The merits and demerits of the Ramp type ADC is also listed at the end of the post. Block Diagram: Principle:  Input voltage is converted into digital equivalent by counting the time taken for the ramp wave to decrease from the magnitude of input voltage to 0V. Construction: The block diagram of the Ramp-type ADC can be divided into two sections as follows:       1. Voltage to time conversion section       2. Time measurement...

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