The Pololu USB AVR Programmer can be configured to accept 3.3V as the target VDD (this can easily be done with our Pololu USB AVR Programmer Configuration Utility available for Windows). However, two output pins on the ISP cable will program your device with 5V. This will probably work, but it is not ideal and could potentially cause damage to the programmer or the target. It might also cause VDD of the target AVR to go up and down wildly. You might consider adding a voltage divider on those pins.
Firtst, thank for your reponse, please add some clarifications:
Can Pololu USB AVR Programmer be configured to accept 3.3V from ‘Ubuntu’?? (not windows)
Does anyone have succefull programing AVR chips in 3.3V, 8/16 mhz, using a Pololu USB AVR Programmer plus a voltage divider on those pins from Ubuntu (Linux) or do you suggest it?
You can configure the Pololu USB AVR Programmer through Linux using PgmCmd from the Pololu USB Software Development Kit. PgmCmd is a command-line status and configuration utility. More information, such as how to compile the code, can be found in the README.txt in the SDK. By the way, I still recommend configuring it via Windows, as it would probably be easier.
I have programmed an Atmega8U2 running at 3.3V with the Pololu USB AVR Programmer in Windows, and I do not expect there be a difference in programming with Linux, as long as the programmer is configured correctly.
Using a level shifter, like the one you linked, would probably work. A resistor voltage divider would also suffice. However, I did not have any voltage divider when I programmed the Atmega8U2.
Hi Jeremy, thanks for your comment, but please clarify me a little more.
Today i receive my Pololu USB AVR Programmer
For example, for attiny85 and 8/16 mhz in 5 volt i think i must connect programmer miso, vdd, sck, mosi, rst, gnd pins directly to a attiny miso, vdd, sck, mosi, rst, gnd pins and also source attiny vdd with 5v externally. It’s ok? or please correct to me.
To program and use in 3v3 volt you say i need to configure the target VDD an also you say ‘However, two output pins on the ISP cable will program your device with 5V…You might consider adding a voltage divider on those pins.’. What are the pins you refer?, Could you explicity show me? And for 8/16 mhz and 3.3 volts, how i must to connect the programmer to the attiny85, please could you show me?
Those connections look correct. The MOSI and SCK pins on the ISP cable were the pins I was referring to.
Again, I was able to program an AVR running at 3.3V without modifying the connections. You might be able to do the same without adding voltage dividers on those pins.
