atmega 128 and communication protocol
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This document describes the Atmega-128 microcontroller and its communication protocols. The Atmega-128 is an 8-bit AVR microcontroller with 128KB of programmable flash memory and 4KB of SRAM. It supports various communication protocols including I2C, SPI, and UART. I2C is described in detail, using only two bidirectional lines to allow flexible data transmission between independently addressable master and slave devices.
atmega 128 and communication protocol
- 1. ATMEGA-128 & COMMUNICATION PROTOCOL PRESENTED BY: Rashmi Deoli Divya Rawat Shalini Ranjan
- 2. ATMEGA 128 DESCRIPTION • It is the high performance • Low power ATMEL • 8 bit AVR • RISC based microcontroller-128 kb programmable flash memory • JTAG interface on chip debugging • It operates between 4.5-5.5 volts • Pin count -64 • No USB interface
- 3. Atmel Atmega128 Overview MEMORY SYSTEM:- There are four separate memory spaces on the AVR. Program space: -128K byte (64Kx16) in-circuit flash programmable. -Can be accessed by program for storage of constants. SRAM Data Memory: -4K bytes -variable storage area EEPROM: -4K bytes -separate data space
- 5. COMMUNICATION PROTOCOL In Atmega-128, there are various types of Protocols:- - I2C (Inter Independent Circuit). - SPI ( Serial Peripheral Interface). - UART (Universal Asynchronous Receiver/Transmitter)
- 6. I2C Characteristics Only 2 Wires Needed On Bus -Serial Data (SDA) -Serial Clock(scl)
- 7. How Does It Work?
- 8. I2C Protocol (cont.) 6. Receiver issues an ACK bit for the byte received 7. Repeat 5 and 6 if more bytes need to be transmitted 8. Master always sends stop condition (P) a. For write transaction (master transmitting), master issues stop condition (P) after last byte of data. b. For read transaction (master receiving), master does not acknowledge final byte, just issues stop condition (P) to tell the slave the transmission is done
- 9. ADVANTAGES • Only two signal lines requires • Flexible data transmission rates • Each device on the bus is independently addressable • Devices have a simple Master/Slave relationship.
- 10. References I2C: http://www-us2.semiconductors.philips.com/acrobat/various/ http://www.esacademy.com/faq/i2c/index.htm http://www.embedded.com/story/OEG20020528S0057