Imagecraft c compiler and development environment for the atmel avr

More documents

Recommendations

Info

ICCV8 for AVR – C Compiler for Atmel AVRmultitasking environment. A ready function is provided for you to ensure that theoperation is completed. This is particularly useful for the EEPROM write function,since writing EEPROM may take a long time.138
ICCV8 for AVR – C Compiler for Atmel AVRSpecific AVR IssuesThere are a wide array of AVR devices available from Atmel, differing in memory sizesand peripherals. This section describes some of the AVR and device specific issues.AVR FeaturesAVR uses the Harvard architecture and separate the program and data memory.See Program Data and Constant Memory.Program memory size is specified in bytes (e.g. M32 has 32K bytes of flash) buteach instruction is at least 2 bytes long. Therefore, program locations encoded inthe instructions are word addresses. When used as storage for literal tables etc.,the program memory is byte addressable using the lpm/elpm family ofinstructions.ICCV8 for AVR programs such as the compiler proper, the assembler and linkeruse byte addresses in most usages and the tools do the appropriate word addressconversion as necessary.The registers are not all general purpose. AVR instructions that use immediatesource operands (e.g. addi, ldi etc.) only operate on the upper 16 registersR16 to R31. There are only 3 set of “pointer” registers: R26/R27 or X, R28/R29 orY, and R30/R31 or Z. Y and Z can use the displacement mode with an offset but Xcannot use such mode.The generated code use two stacks (see Program Data and Constant Memory),the native hardware stack for CALL return addresses and a software stack usingthe Y pointer. While this makes it more challenging to ensure that both stackshave sufficient space, the alternative of using a single stack generatessubstantially more code.Device-Specific InstructionsDevices with 8K or less bytes of program memory do not support the jmp and callinstructions, and only the rjmp and rcall relative instructions. The initial generationof the AVR (sometimes known as “classic” AVRs) do not have the newer instructionssuch as the multiply instructions and the extended lpm instructions.139
Page 2 and 3:
ICCV8 for AVR - C Compiler for Atme
Page 4:
Page 8 and 9:
Page 10 and 11:
Page 12 and 13:
Page 14 and 15:
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Page 24 and 25:
Page 26 and 27:
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89: ICCV8 for AVR - C Compiler for Atme
Page 165 and 166: TOOL REFERENCESMISRA / Lint Code Ch
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 204:
show all

Imagecraft c compiler and development environment for the atmel avr

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?