ATMega chip full datasheet - UCSD Department of Physics

ATmega48A/PA/88A/PA/168A/PA/328/P21.5Frame Formats ....................................................................................................20821.6Data Transfer ......................................................................................................21021.7AVR USART MSPIM vs. AVR SPI ......................................................................21221.8Register Description ............................................................................................21322 2-wire Serial Interface .......................................................................... 21622.1Features ..............................................................................................................21622.22-wire Serial Interface Bus Definition ..................................................................21622.3Data Transfer and Frame Format ........................................................................21822.4Multi-master Bus Systems, Arbitration and Synchronization ...............................22022.5Overview of the TWI Module ...............................................................................22322.6Using the TWI ......................................................................................................22522.7Transmission Modes ...........................................................................................22922.8Multi-master Systems and Arbitration ..................................................................24222.9Register Description ............................................................................................24323 Analog Comparator ............................................................................. 24823.1Overview .............................................................................................................24823.2Analog Comparator Multiplexed Input .................................................................24823.3Register Description ............................................................................................24924 Analog-to-Digital Converter ................................................................ 25224.1Features ..............................................................................................................25224.2Overview .............................................................................................................25224.3Starting a Conversion ..........................................................................................25424.4Prescaling and Conversion Timing ......................................................................25524.5Changing Channel or Reference Selection .........................................................25724.6ADC Noise Canceler ...........................................................................................25824.7ADC Conversion Result ......................................................................................26324.8Temperature Measurement .................................................................................26324.9Register Description ............................................................................................26425 debugWIRE On-chip Debug System .................................................. 26925.1Features ..............................................................................................................26925.2Overview .............................................................................................................26925.3Physical Interface ................................................................................................26925.4Software Break Points .........................................................................................27025.5Limitations of debugWIRE ...................................................................................27025.6Register Description ............................................................................................2708271D–AVR–05/11v