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{{Warningbox|This section was recently updated for ChipWhisperer 5. The old version can be found here: https://wiki.newae.com/V4:CW1173_ChipWhisperer-Lite/AVR_Programmer.}}
The CW1173 and CW1200 have built-in support for programming either Atmel AVR or Atmel XMEGA device. This is designed to allow you to program our target boards (including the built-in XMEGA target).
The AVR device programmer requires four connections to the target: RESET, MOSI, MISO, SCK. See [[#20-Pin_Connector]] for details of AVR programming pin connections.
==== Accessing the Programming Programmer ====
The default SPI data rate for the programmer is too fast for devices which are running slower than 2 MHz. If programming a device with a clock source slower than 2 MHz, you will need to enable the "Slow Clock Mode". In "Slow Clock Mode" the entire SAM3U and FPGA clock is changed from 96 MHz to 12 MHz. Note the default fuse bytes for a virgin ATMega328P result in a 1 MHz clock, so you will need to use "slow clock mode" to program the correct fuse bytes, after which point you will not need to use "slow clock mode".
To enable slow clock mode, call <code>program_target</code> with an additional <code>slow_clock = True</code> parameter:
<syntaxhighlight lang=python>
cw.program_target(scope, prog, "<path to hex file", slow_clock=True)
</syntaxhighlight>
<blockquote>'''note'''
The 'slow clock mode' is used to provide a slower SPI clock than would otherwise be possible. When switching into 'slow clock mode' it will cause all DCM blocks in the FPGA to become unlocked. You will need to reset the DCM blocks, or simply restart call <code>default_setup()</code> again (this will reset the CW-Capture software and run the setup scriptserial pins, so you'll have to swap them again if you're using a Notduino target).
</blockquote>
==== Programming the Fuses ====
By default the AVR programmer allows you to modify the LOW fuse byte only, as this byte controls the clock source selection. To change the value of the fuse byte, you'll need to manually setup the programmer:
<syntaxhighlight lang=python>avr_programmer = prog(slow_clock=False) # Press call with slow_clock = True to enable the "Read Fuses" buttonslow clockavr_programmer.scope = scopeavr_programmer.open()avr_programmer.find()</syntaxhighlight> Once that's accomplished, and the values should readFuse() and writeFuse() methods can be populated# Specify used to read and write the new low fuse bits, respectively: <syntaxhighlight lang=python>fuse_vals = avr_programmer.readFuse(<value>)# Hit "Write Fuses"avr_programmer.writeFuse(<value>, <lfuse>)</syntaxhighlight> with <value> corresponding to one of the following: "low", "high", or "extended".
See [http://eleccelerator.com/fusecalc/fusecalc.php?chip=atmega328p an Online Fuse Calculator] to better understand what the values mean.
The low fuse byte must be changed to <code>D0</code> to use the external clock provided by the ChipWhisperer toolchain.
</blockquote>
==== Programming the Flash Troubleshooting ==== Programming the flash is accomplished by selecting the new .hex file in the "Find" menu, and pressing the "Erase/Program/Verify FLASH" button. The "Status" line will show the following information:
