Atmel AT90S1200, Manual, Page: 69 / 72

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AT90S1200
0838H–AVR–03/02
Table of Contents
Features................................................................................................. 1
Pin Configuration.................................................................................. 1
Description ............................................................................................ 2
Block Diagram ...................................................................................................... 2
Pin Descriptions.................................................................................................... 3
Crystal Oscillator................................................................................................... 3
On-chip RC Oscillator ........................................................................................... 4
Architectural Overview......................................................................... 5
General Purpose Register File ............................................................................. 6
ALU – Arithmetic Logic Unit.................................................................................. 6
In-System Programmable Flash Program Memory .............................................. 6
Program and Data Addressing Modes.................................................................. 7
Subroutine and Interrupt Hardware Stack ............................................................ 8
EEPROM Data Memory........................................................................................ 9
Instruction Execution Timing................................................................................. 9
I/O Memory ......................................................................................................... 10
Reset and Interrupt Handling.............................................................................. 12
Sleep Modes....................................................................................................... 19
Timer/Counter0 ................................................................................... 20
Timer/Counter0 Prescaler................................................................................... 20
Watchdog Timer.................................................................................. 23
EEPROM Read/Write Access ............................................................. 25
Prevent EEPROM Corruption ............................................................................. 26
Analog Comparator ............................................................................ 27
I/O Ports............................................................................................... 29
Port B.................................................................................................................. 29
Port D.................................................................................................................. 34
Memory Programming........................................................................ 37
Program and Data Memory Lock Bits................................................................. 37
Fuse Bits............................................................................................................. 37
Signature Bytes .................................................................................................. 37
Programming the Flash and EEPROM............................................................... 37
Parallel Programming ......................................................................................... 38
Parallel Programming Characteristics ................................................................ 43
Serial Downloading............................................................................................. 44
Serial Programming Characteristics ................................................................... 47