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--- flash_the_atmega [2013/10/03 15:48] – breaker27
+++ flash_the_atmega [2023/03/01 19:40] (current) – [Using flash scripts] breaker27
@@ Line 1: / Line 1: @@
 ====== Get the firmware ======
-You can either take a pre-built firmware package from [[http://www.smarthomatic.org/builds/builds.html]] or build your own firmware. If you take the prebuilt package, extract it and continue with "Flashing the controller".
+You can either take a pre-built firmware package from [[http://www.smarthomatic.org/builds/builds.html]] or [[build your own firmware|build your own firmware]]. If you take the prebuilt package, extract it to a directory of your choice.
+====== Three different storage areas ======
+Every microcontroller has three parts that can be flashed (written):
+  * Three **fuse bytes** contains microcontroller specific configuration bits. These should only be set once.
+  * The **flash memory** contains the firmware. It can be overwritten about 10.000 times.
+  * The **EEPROM memory** contains (firmware) configuration data. It is also written to by the device in normal operation. It can we overwritten about 100.000 times.
+{{danger.gif}} **In general, it's a good idea to only flash what you need to, because of the limited amount of possible write cycles.**
 ====== Programming fuses ======
-If you have built your binaries by yourself with "make", your fuse settings should be available as files **lfuse.bin**, **hfuse.bin** and **efuse.bin** in the bin subdirectory. You can write these fuses with
+===== Using a make rule =====
+If you build your binaries by yourself with "make", your fuse settings should be available as files **lfuse.bin**, **hfuse.bin** and **efuse.bin** in the bin subdirectory **of the device you want to flash**. You can write these fuses with:
 <code>
@@ Line 13: / Line 25: @@
 Be sure about the fuse settings you want to write in your microcontroller. With wrong fuse settings, your microcontroller might not be accessible anymore!
-====== Programming your own fuses ======
+===== Calling avrdude directly =====
-Depending on the use of an external crystal or the internal RC oscillator, you have to use different fuse settings.
+If you are creating a new or modified SHC device, you may want to write other than the default fuses. You can do so with:
-Please see the text files in the [[http://www.smarthomatic.org/builds/builds.html|downloadable builds]] for the required fuse settings.
+<code>
+avrdude -p ATMEGA328P -U lfuse:w:0x??:m
+</code>
-You can write fuses by calling e.g.
+(replace ?? by the hex value for the needed fuse settings and use "lfuse", "hfuse" or "efuse" accordingly).
+===== Strange avrdude error messages =====
+Some fuses only use a part of their bits. If you set such a fuse, avrdude may complain at verification that it read out another value than it wrote.
+Writing the EFuse of the ATMega168 or 328 returns a value of only the last 3 bits (upper 5 unused), so a value of xxxxxyyy is read out as 00000yyy. Example:
 <code>
-avrdude -p ATMEGA328P -U lfuse:w:0x??:m
+avrdude: verification error, first mismatch at byte 0x0000
+xfc != 0x04
+avrdude: verification error; content mismatch
+</code>
+Don't worry. The warning is only returned because avrdude does not know that the upper 5 bits are always 1 (as per spec).
+====== Flashing the firmware / eeprom ======
+===== Using flash scripts =====
+After setting up avrdude, you can flash the firmware by calling the flash scripts
+  * **flash.cmd** / **flash.sh** for flashing firmware, eeprom and fuses
+  * **flash_firmware.cmd** / **flash_firmware.sh** for flashing only the firmware
+===== Using a make rule =====
+If you have the source code on your machine, you can flash the firmware with the following command from the firmware subdirectory:
+<code>
+make program
 </code>
-(replace ?? by the needed fuse settings and use "lfuse", "hfuse" or "efuse" accordingly.
+===== Calling avrdude directly =====
-===== Flashing the controller =====
+If you want to call avrdude by hand you can flash everything with:
 <code>
-pi@ninjablock ~/test/smarthomatic/firmware/shc_basestation $ avrdude -P /dev/ttyACM0 -c STK500 -p m328p -U flash:w:bin/ohc_basestation.hex -U lfuse:w:0xf7:m -U hfuse:w:0xd1:m -U efuse:w:0x07:m
+avrdude -p m328p -U flash:w:shc_basestation.hex -U eeprom:w:shc_basestation.e2p:r -U lfuse:w:lfuse.bin:r -U hfuse:w:hfuse.bin:r -U efuse:w:efuse.bin:r
 </code>
+(leave one part "-U ..." out to flash only a part).