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Gerd's AVR simulator

• Simulates AVR 8-bit microcontrollers of any type (ATtiny, ATmega, etc.) in assembler.
• Just as if you would jump into the controller and you'll see what it does with your source code.
• Necessary is the source code file only (in *.asm format).
• Assembles the source code with the built-in assembler gavrasm, fast and reliable.
• Allows control over registers, flags, memories, ports, timer/counters, AD converter, etc.
• All is displayed in a convenient form and available only if really needed.
• Can be used to devellop assembler software from scratch as well as for existing projects.
• Well suited even for older projects because of the support for all older AVR chip types.
• Stand-alone solution: includes anything needed for all its features, no additions necessary, no dependencies, no installation necessary. Works out of the box "like a charm" (a new user).
• Useful to understand AVR controller's hardware and to learn assembler from scratch: each additional codeline can be assembled and simulated, and it can immediately be seen what it does within the controller. Forget the "Assembler is complicated to learn!" statements: it is easier to learn than any other language and is highly transparent with the simulator.

1 Description

1. Simple handling, no extended learning phase required,
   
2. Works under Windows and Linux, 64-bit executables downloadable,
   
3. Lazarus-Pascal source code available for free for own modifications,
   
4. Fast and comfortable start of new assembler projects, fills in standard text frames for structured source code in a short or in a comprehensive format, for linear as well as for interrupt-oriented programs,
   
   
   
   Left the comprehensive version, right with interrupt vectors,
   
   A short version without any extras is also available,
   
5. From Version 1.8 on a comfortable device selector is on board, that allows to select AVRs (types and packages) by selectable hardware requirements,
   
   
   
   
6. Editor for modifying of the assembler source code with several helpful features,
   
   
   
   
7. The editor, from version 1.7 on, has a syntax highlighter which provides multiple opportunities for its configuration:
   
   
   
   
8. Forgot the mnemonic of an instruction in AVR assembler, forgot how many clock cycles it needs or which flags are affected? No problem in avr_sim. From Version 2.1 on an instruction list comes up and you can search and find what you need,
   
   
   
   
9. Display of header symbols, ports and interrupts of the applied AVR type,
   
   
   
   
10. Display of the hardware configuration for PDIP-/SOIC- and QFN-packages,
    
    
    
    
11. Insert the hardware into the source code by simply typing F2:
    
    
    
12. Internal assembler gavrasm for quick modification and assembling of code,
    
    
    
    
13. Comfortable setting and clearing of breakpoints, storing breakpoints in and loading them from the project file,
    
    
    
    
14. From version 2.3 on: Scan- and alarm function: counts, beeps and/or stops if a register or a register pair, a portregister or a portregister pair, a SRAM location or a SRAM pair is written, written with a preselected value or read,
    
    
    
    
15. Control of the simulation in a simulator window,
    
    
    
    
16. Simple overview over I/O ports and timers,
    
    
    
    
17. Display of SRAM content,
    
    
    
    
18. Display of EEPROM content as well as correct Write and Read operations,
    
    
    
    
19. Display and simulation of the watchdog timer,
    
    
    
    
20. Display, simulation and manipulation of ADC channels, from version 2.7 on including configurable differential channels and temperature measurements, und
    
    
21. as extra a design aid with a 12/16-key resistor matrix and voltage input via keyboard, from version 2.7 on including internal reference voltages,
    
    
    
    and display of the key's voltages,
    
    
    
    
22. Configurable four-channel scope for displaying polarity changes on output compare pins or on any available I/O pin of the device,
    
    
    
    
23. Scope display for R/2R analog values on ports with configurable resolution and in up to four different channels simultanously in selectable colors,
    
    
    
24. Scope display of internal Digital-to-Analog converters for those AVR types that have these available,
    
    
    
25. From version 2.8 on: scope channels can be displayed as stack, so the different channels do not overwrite others.
    
    You can now fix the time scale of the display.
26. You need a short view some hundred lines above in your code? Just open a new codeview window, your editor is not affected by this, try copy and paste between the two code windows,
27. Simple and fast display of decimals in registers and of register pairs - place the mouse over the register and you'll get what you need!
28. From version 2.5 on: register save mode (for all changes of registers) and trace mode (for all configurable register-, portregister- and SRAM-content) as .csv file for export to an external spreadsheet.
29. From version 2.6 on: Simple jumps (Jump to) during simulation, also as call to a subroutine (Call) or for simulating an interrupt with cleared I-flag (Call ISR),
    
    
    
    
30. New in version 2.9: avr_sim now simulates interrupt-driven transmit and receive via the serial UART(s):
    
    
    
    
31. New from version 2.9: avr_sim now performs a user statistic on the internet. Counted are the applied AVR types and the open windows during simulation. Don't be afraid: all is anonymous and you can see in your browser's address field, what has been sent!

2 Download

2.4 Handbook for use

4 Statistics

4.1 Monthly accesses

4.2 Accesses by versions

4.3 Accesses by executables vs. sources

5 Links to uses and users of avr_sim

• The starter course here uses avr_sim as instrument for introducing the first assembler projects and to visualize the effect of assembler instructions.
• The micro-beginner course here uses avr_sim to understand key AVR instruction execution and basic techniques in assembler programming of AVRs.
• This webdocument describes the execution of codes by an AVR and uses avr_sim to show what is going on internally.
• This document uses avr_sim to visualize the execution of interrupts.
• This page on handling date and time demonstrates the handling of date and time info by using avr_sim.
• This demonstrates of avr_sim's built-in device selector.
• This here uses avr_sim's ADC simulator to follow program execution with key encoders.
• This uses avr_sim's capability to measure execution times of delay loops in LCD applications.