Download to read offline
AVR Microcontroller-Introduction, Features
- 1.
- 3. AVR FAMILY OVERVIEW •Classic AVR
- 4. AVR FAMILY OVERVIEW •Mega AVR Program memory: 4K-256K Package:28-100 pins Extensive peripheral set, extended instruction set.
- 5. AVR FAMILY OVERVIEW •Tiny AVR Program memory: 1K-8K Package:8-28 pins limited peripheral set and instruction set.
- 6. AVR FAMILY OVERVIEW •Special purpose AVR
- 7. GPRs in theAVR
- 8.
- 9. AVR Data Memory •GPRs- 2B • IO Registers- 64B • SRAM-(128 B to 4KB)
- 10.
- 11. Using instructions withthe Data Memory • LDS (LoaD direct from Data Space): LDS Rd, K
- 12. • STS(STore directto data Space): STS K, Rr
- 13.
- 14. AVR DATA FORMATAND DIRECTIVES • Data format Representation: Hex Numbers Decimal numbers Binary numbers ASCII characters
- 15. Assembler Directives • .EQU •.ORG • .INCLUDE Segment` Directive Description Header .DEVICE Defines the type of the target processor and the applicable set of instructions (illegal instructions for that type trigger an error message, syntax: .DEVICE AT90S8515) .DEF Defines a synonym for a register (e.g. .DEF MyReg = R16) .EQU Defines a symbol and sets its value (later changes of this value remain possible, syntax: .EQU test = 1234567, internal storage of the value is 4- byte- Integer) .SET Fixes the value of a symbole (later redefinition is not possible) .INCLUDE Includes a file and assembles its content, just like its content would be part of the calling file (typical e.g. including the header file: .INCLUDE "C: avrtoolsappnotes8515def.inc") Code .DB Inserts one or more constant bytes in the code segment (could be numbers from 0..255, an ASCII-character like 'c', a string like 'abcde' or a combination like 1,2,3,'abc'. The number of inserted bytes must be even, otherwise an additional zero byte will be inserted by the assembler.) .DW Insert a binary word in the code segment (e.g. produces a table within the code) .LISTMAC Macros will be listed in the .LST-file. (Default is that macros are not listed) .MACRO Beginning of a macro (no code will be produced, call of the macro later produces code, syntax: .MACRO macroname parameters, calling by: macroname parameters) .ENDMACRO End of the macro Everywhere .ORG Defines the address within the respective segment, where the assembler assembles to (e.g. .ORG 0x0000) .EXIT End of the assembler-source code (stops the assembling process)
- 18. Structure OF AVRAssembly Language
- 19.
- 21. PROGRAM COUNTER(PC) IN AVR Program Counter& Program ROM space in the AVR: • Address of the next instruction to be executed. • As the CPU fetches the opcode from program ROM, the PC is incremented by 1, which points to the next instruction. • Size of PC—(14 bit to 22-bit). • In AVR microcontrollers, each flash memory location is 2-bytes wide. • e.g. ATMega32---> ROM size is 32KB organized as 16KB x 2B.
- 23. ROM memory mapin AVR family
- 24. Placing code inprogram ROM
- 25. ROM width inthe AVR AVR is word-addressable.
- 26. Harvard Architecture in the AVR HarvardArchitecture in the AVR:
- 27. Instruction size ofthe AVR
- 28.
- 33. FEATURES 1. RISC processorshave a fixed instruction size. 2. RISC processors have a large number of registers. 3. RISC processors have small instruction set. 4. >95% instructions are executed with only single clock cycle. 5. RISC processors have separate buses for program and data. • In RISC, there are 4 sets of buses- • 1) a set of data buses for carrying data (operands) in and out of CPU. • 2) a set of address buses for accessing the data. • 3) a set of buses to carry the opcodes. • 4) a set of address buses to access the opcodes.
- 34. FEATURES 5.RISC uses LOAD/STOREarchitecture. 6. RISC instructions are implemented using hardwire method. Hardwiring of RISC instructions takes no more than 10% of the transistors.
Editor's Notes
- #26 Advanced Microcontrollers