Hi,
Anybody know the best way to interface a 3.3V SPI device to a 5V Arduino (actually just the Atmel 328 chip)? The SPI device I have is a Hope RFM12 wireless transceiver (http://www.hoperf.com/upload/rf/RFM12B.pdf).
Powering the RFM12 is no problem but the SPI data lines will be at different levels.
I just ordered an LCD from Limor that comes with a 4050 chip to do the voltage conversion and I'm wondering if this chip would work in my case (or maybe there's something simpler?)
thanks in advance,
Phil
3.3V SPI device with a 5v ATMEGA328?
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
-
- Posts: 46
- Joined: Sun Oct 23, 2011 11:17 am
Re: 3.3V SPI device with a 5v ATMEGA328?
I haven't used this circuit myself, but it seems to have a good pedigree. It's said to be bidirectional and just uses a MOSFET and two resistors.
http://www.rocketnumbernine.com/2009/04 ... -converter
The schematic from that page is
http://www.rocketnumbernine.com/2009/04 ... -converter
The schematic from that page is
- balloon-pilot
- Posts: 6
- Joined: Thu Feb 16, 2012 9:17 am
Re: 3.3V SPI device with a 5v ATMEGA328?
Excellent website, thanks for the link. From what I read, the spi output lines from the transceiver will interface clean to the atmel (will be above .6V, and the spI input lines might just need a divider to drop the atmel's 5v down to 3.3. I'll wire it up and see what happens (success or smoke).
- Franklin97355
- Posts: 23911
- Joined: Mon Apr 21, 2008 2:33 pm
- philba
- Posts: 387
- Joined: Mon Dec 19, 2011 6:59 pm
Re: 3.3V SPI device with a 5v ATMEGA328?
Lots of good ideas here.
I'm in the process of moving to 3.3v only. I'm using teensy 2 with the regulator in a couple of projects and like it a lot. Cost effective, small, breadboard friendly. There are only a few cases where I need more that 3.3V and I'd rather deal with them than the other way around. Feeding a 5V device 3.3V doesn't fry it.
I'm in the process of moving to 3.3v only. I'm using teensy 2 with the regulator in a couple of projects and like it a lot. Cost effective, small, breadboard friendly. There are only a few cases where I need more that 3.3V and I'd rather deal with them than the other way around. Feeding a 5V device 3.3V doesn't fry it.
Please be positive and constructive with your questions and comments.