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+simavr - lean and mean Atmel AVR simulator for linux
+======
+
+/simavr/ is a new AVR simulator for linux, or any platform that uses avr-gcc. It uses
+avr-gcc own register definition to simplify creating new targets for supported AVR
+devices. The core was made to be small and compact, and hackable so allow quick
+prototyping of an AVR project. The AVR core is now stable for use with parts
+with <= 128KB flash, and with preliminary support for the bigger parts. The
+simulator loads ELF files directly, and there is even a way to specify simulation
+parameters directly in the emulated code using an .elf section. You can also
+load multipart HEX files.
+
+Supported IOs
+--------------
+* /eeprom/
+* /watchdog/
+* /IO ports/ (including pin interrupts)
+* /Timers/, 8 &16 (Normal, CTC and Fast PWM, the overflow interrupt too)
+* The /UART/, including tx & rx interrupts (there is a loopback/local echo test mode too)
+* /SPI/, master/slave including the interrupt
+* /i2c/ Master & Slave
+* External /Interrupts/, INT0 and so on.
+* /ADC/
+* Self-programming (ie bootloaders!)
+
+Emulated Cores (very easy to add new ones!)
+--------------
++ AT90USB162 (with USB!)
++ ATMega1280
++ ATMega128
++ ATMega16M1
++ ATMega164/324/644
++ ATMega48/88/168/328
++ ATMega8
++ ATTiny25/45/85
++ ATTIny44/84
++ ATTiny2313
++ ATTiny13
+
+Extras:
+-------
+* /gdb/ support fully work (gdb server) including some pretty cool “passive modes”.
+* There is also very easy support for “VCD” (Value Change Dump) that can be visualized
+graphicaly as “waveforms” with tools like /gtkwave/ (see bellow).
+* There are a few examples of real life firmwares running on simavr, including OpenGL rendering of the display…
+* There is support /Arduino/, but no integration to the IDE
+
+*Note:* a mailinglist/google group now exists
+You can also join *#simavr* on Freenode for a very quiet IRC channel.
+
+VCD Support -- built in logic analyzer
+-----------
+/simavr/ can output most of it's pins, firmware variables, interrupts and a few other
+things as signals to be dumped into a file that can be plotted using gtkwave for
+further, precise analysis.
+A firmware can contain instructions for /simavr/ to know what to trace, and the file is
+automatically generated.
+Example:
+
+`const struct avr_mmcu_vcd_trace_t _mytrace[] _MMCU_ = {
+ { AVR_MCU_VCD_SYMBOL("UDR0"), .what = (void*)&UDR0, },
+ { AVR_MCU_VCD_SYMBOL("UDRE0"), .mask = (1 << UDRE0), .what = (void*)&UCSR0A, },
+};`
+
+Will tell /simavr/ to generate a trace everytime the UDR0 register changes and everytime
+the interrupt is raised (in UCSR0A). The *_MMCU_* tag tells gcc that it needs compiling,
+but it won't be linked in your program, so it takes literally zero bytes, this is a code
+section that is private to /simavr/, it's free!
+A program running with these instructions and writing to the serial port will generate
+a file that will display:
+`$ ./simavr/run_avr tests/atmega88_example.axf
+AVR_MMCU_TAG_VCD_TRACE 00c6:00 - UDR0
+AVR_MMCU_TAG_VCD_TRACE 00c0:20 - UDRE0
+Loaded 1780 .text
+Loaded 114 .data
+Loaded 4 .eeprom
+Starting atmega88 - flashend 1fff ramend 04ff e2end 01ff
+atmega88 init
+avr_eeprom_ioctl: AVR_IOCTL_EEPROM_SET Loaded 4 at offset 0
+Creating VCD trace file 'gtkwave_trace.vcd'
+Read from eeprom 0xdeadbeef -- should be 0xdeadbeef..
+Read from eeprom 0xcafef00d -- should be 0xcafef00d..
+simavr: sleeping with interrupts off, quitting gracefully`
+
+And when the file is loaded in gtkwave, you see:
+
+
+You get a very precise timing breakdown of any change that you add to the trace, down
+to the AVR cycle.
+
+Example:
+--------
+/simavr/ is really made to be the center for emulating your own AVR projects, not just
+a debugger, but also the emulating the peripherals you will use in your firmware, so
+you can test and develop offline, and now and then try it on the hardware.
+
+You can also use /simavr/ to do test units on your shipping firmware to validate it
+before you ship a new version, to prevent regressions or mistakes.
+
+/simavr/ has a few 'complete projects/ that demonstrate this, most of them were made
+using real hardware at some point, and the firmware binary is /exactly/ the one that
+ran on the hardware. The key here is to emulate the /parts/ or peripherals that
+are hooked to the AVR. Of course, you don't have to emulate the full hardware, you just
+need to generate the proper stimulus so that the AVR is fooled.
+
+HD77480 LCD Board Demo
+----------------------
+
+
+This example board hooks up an Atmega48 to an emulated HD77480 LCD and display a running
+counter in the 'lcd'. Everything is emulated, the firmware runs exactly like this
+on a real hardware.
+
+
+And this is a gtkwave trace of what the firmware is doing. You can zoom in, measure etc
+in gtkwave, select trades to see etc.
+
+Quite a few other examples are available!
projects / simavr / commitdiff
