ATmega328 Microcontroller and the Functions of Its Components - Case Study Example

ATmega328 Microcontroller (Name) (University) Introduction The ATmega328 is a chip miniature computer containing a core processor memory and input and outputs that are programmable which uses both an ISP flash memory of 32 KB with capabilities including read-while-write (atmel, 2015). The micro controller is part of the megaAVR series and is a product of Atmel (Svendsli, 2013). The ATmega328 is mostly utilized in systems that are autonomous and related projects where a micro controller that is not complex, uses low power and has low costs is required. The Arduino uno and Arduino nano are the most common developmental models that have been used under this micro controller. Features of the ATmega328 The ATmega328 microcontroller has an elevated performance with a low power AVR 8-bit micro controller. Its sophisticated RISK structural design allows for 131 powerful commands with an execution of the clock cycle that is the most independent. The general purpose working register operates at 32* 8 while its operation is fully static. It has up to 20 MIPS throughput at 20 megahertz. The multiplier is additionally on the chip with a double cycle (Butchy et al., 2012). The memory segments of the ATmega328 are high endurance and non volatile. The flash program memory programs itself within the system and possesses 4/8/16/32K Bytes. EEPROM has 256/512/512/1K Bytes while the static random access memory has 512/1K/1K/2K Bytes. It has cycles that allow for the writing and erasing of information. The cycle owns 10000 flashes and an Electrically Erasable Programmable Read-Only Memory of 100000. The preservation of data capacity of ATmega328 is at 20 years under temperature conditions of 85 degrees and 100 years at 25 degrees. The boot lock section is optional while the lock bits are independent. Within the micro controller there exists a programming lock for the security of software. The peripheral features of the micro controller are inclusive of two 8 bit timers which have a separate prescaler and a compare mode that comes with the timer although has distinct purposes. The counter of the ATmega328 is real time and its oscillator is located separately. There are 6 pulse- width modulators (PWM) channels to the micro controller. The analogue to digital converter (ADC) is an 8 channel 8 bit when TQFP and QFN/MLF are put together. The temperature extent of the microcontroller has a 6 channel PDIP package that is a 10 bit analogue to digital converter. The serial universal asynchronous receiver/transmitter is programmable and there is a serial interface that is a serial peripheral interface (SPI) master/slave. The serial interface is additionally a two wire byte oriented interface. It is furthermore a Phillips I2C compatible. The timer is programmable and it has an on-chip oscillator that is separate. Change of pin triggers an interrupt and wake up activity. The microcontroller has special features such as brown out detector that is programmable and a power on reset. The oscillator is internally calibrated and there are interrupt sources that are both internal and external. The six modes of sleep in the microcontroller include: idle, analogue to digital converter noise lessening, power down, power save, stand by and a standby that is extended. The input and output packages have features such as 23 input and output lines that programmable. The PDIP is a 28 pin. The TQPF is a 32 lead with a QFN/MLF 28 pad and a QFN/MLF 32 pad. The temperature ranges from 40 degrees to 85 degrees. The speed rating is 0 to 4 megahertz at 1.8 to 5.5V, 0 to 10 megahertz at 2.7 - 5.5.V and 0 – 20 megahertz at 4.5 - 5.5V. Power Consumption is at 1 megahertz, 1.8V, 25°C with an Active Mode: 0.2 mA and a Power-down Mode: 0.1 μA. The Power-save Mode is at 0.75 μA (Including 32 kHz RTC) Main function of each component of the microcontroller Figure 1: Block figure of the system The particular function of the central processing unit is to ensure that programs are executed correctly. The CPU must thus possess the capability of accessing memories in the system, have control over the peripherals, carry out calculations and handle interrupts. There is a 32 x 8 bit registers that are general purpose that are obtained from the fast access register file. Consequently, ALU operation is allowed. From the thirty two registers, six can be used as tri 16 bit register pointers for addressing of data space as indirect addresses. The ALU supports operations of arithmetic and logic nature in between a constant and a register or in between registers. The Input/Output memory room has 64 addresses of the secondary functions of the CPU. With its extended space, the ATmega328 has extra space that allows the use of instructions. The ALU performs in direct correlation with the 32 general purpose working registers. The categories of the ALU functions are bit functions, logical and arithmetic operations. The status register has information about results of the most recently carried out arithmetic instruction. The information that the status register possesses can be used to change the flow of programs so that conditional operations can be performed. Succeeding ALU operations is when the status register gets updated. In the event of entering an interrupt schedule, the status register is not automatically updated or restored after the interrupt thus the operation needs to be performed by software. The file register for general purpose is set for superior commands. It is supported by four I/O schemes. Every one of the register has a data memory address that directly maps them to the 32 locations of the data space of the user. The memory organization used provides for easy access to the registers. The diagram below shows the CPU general purpose working registers. Figure 2: General purpose working registers The internal oscillator frequency The internal RC oscillator is calibrated and provides an approximate of 8 megahertz of clock. The oscillator depends on voltage and temperature; however, it can be calibrated accurately by the user (Kumar, 2013). Should the 8 megahertz frequency exceed the specification of the device, the fuse is programmable to partition the internal occurrence by 8. There is a 128 kilohertz internal oscillator that has low voltage and a nominal frequency of 3 volts and 25 degrees Celsius. Voltage operating range The voltage operating range of the ATmega328 is between 1.8 to 5.5V. RAM, EEPROM and In-system bytes The ATmega328 has a 4K/8K bytes of In-System Programmable Flash which possesses the capabilities of Read-While-Write. Has The micro controller Electrically Erasable Programmable Read-Only Memory of 256/512/512/1K bytes EEPROM. This memory is a non volatile memory and is used in devices where information can be stored in the absence of power. ATmega328 has a 512/1K/1K/2K bytes static random access memory (SRAM). Pins The ATmega328 has nine pins. The types of pins are inclusive of the digital pin, I/O, digital analogue converter and that for power. Functions of pins The VCC is a digital supply voltage while the GND supplies power from the ground. Port B is an I/O port with an 8 bit bi directional which has resistors that are internally pull-up. The drive characteristics of the output buffers of the port possess both source capability and high sink. When the port B pins perform as inputs, they are pulled low so that they can supply current when the pull-up resistors get energized. Port C is an I/O port with resistors that are internally pulled up and are dutifully chosen for each bit. The drive distinctiveness of the output buffers of the port are similar to those of port B where there is source capability and high sink. Comparable to port B, when acting as inputs, they are pulled low so that they can resource current when the pull-up resistors are in activity. The PC6/RESET is an Input/Output pin when the RSTDISBL Fuse is automatic. Should the fuse be deprogrammed, PC6 is consequently utilized as a retune input. A level that is reduced in this pin for a longer period than the least amount of pulse duration is bound to generate a reset still in the event of the clock failing to run. As explained in port B and C, port D is an Input/Ouotput port with an 8 bit bi directional which has resistors that are internally pull-up. The drive characteristics of the output buffers of the port possess both source capability and high sink. When the port B pins operate as inputs, they are lowered so that they can supply current when the pull-up resistors are in activity. Port D however has special features where it can operate as an external interrupt supply. It also serves as an USART external clock and a external output when correctly configured (Kunikowski, 2015). The AVcc pin provides voltage supply for the analogue digital converter while AREF is the pin for the analogue reference of the analogue to digital converter. The ADC7:6 pin has the the TQFP and QFN/MLF package only and acts as an analogue input to the analogue digital converter. These pins access power form the analogue supply and they serve as 10 bit analogue digital converter channels. References AVR ATmega328 microcontroller. Retrieved from http://www.atmel.com/ accessed on 9th October 2015 Buchty, R., Heuveline, V., Karl, W., & Weiss, J. P. (2012). A survey on hardware‐aware and heterogeneous computing on multicore processors and accelerators. Concurrency and Computation: Practice and Experience, 24(7), 663-675. Kumar, P. U., & Sarma, G. K. (2013). AN EMBEDDED SYSTEM DESIGN IN AUTOMATION OF STREET LIGHTS USING ATMEGA 8535L MICROCONTROLLER. International Journal of Science, Engineering and Technology Research, 2(6), pp-1380. Kunikowski, W., Czerwiński, E., Olejnik, P., & Awrejcewicz, J. (2015). An Overview of ATmega AVR Microcontrollers Used in Scientific Research and Industrial Applications. Pomiary, Automatyka, Robotyka, 19. Svendsli, O. J. (2013). Atmel’s Self-Programming Flash Microcontrollers. Systementwicklungsprojekt-Thomas Kittel. Read More