Comments on: Tutorial: 3.3V hacking for Arduino Nano https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/ Electronics, Computers at leisure time Mon, 25 Apr 2016 10:42:50 +0000 hourly 1 https://wordpress.org/?v=6.1.1 By: Tochinet https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-70 Mon, 25 Apr 2016 10:42:50 +0000 https://www.ba0sh1.com/?p=591#comment-70 Very nice tutorial. I alays wondered why nobody produced a 3V3 Nano!

To some commenters, the idea here is to make all I/Os (and also VRef/ADCs etc) work at 3V3, even if there is some Vin or VUSB present ! That can’t be done without HW modifications.

FYI, overclocking at 16MHz has been done by JeeLabs for years without any report of problems.

Note also that MCP regulators only accepts voltages up to 6V. That’s OK for USB, but the nano original specs states that Vin can accept 7V to 12V (or even 6V to 20V).

]]> By: Craig https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-69 Mon, 01 Feb 2016 08:58:38 +0000 https://www.ba0sh1.com/?p=591#comment-69 Other good alternatives for the regulator, which are half the price (in the UK at least), are the MicroChip MCP1825S-3302E, or TC1262-3.3VDB

]]> By: Denis https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-68 Wed, 21 Oct 2015 21:07:37 +0000 https://www.ba0sh1.com/?p=591#comment-68 I am powering my Nano V3 Clone (CH340G USB/serial) with 4.2V on Vin. Then the buildin regulator gives 3.3V to the AVR and it can also drive 3.3V modules on the 5V-Pin (a.k.a. 3.3V). The clock is at 16MHz. The downside is that I can not use the USB/serial at the same time.

]]> By: Carlos https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-67 Sat, 11 Apr 2015 22:51:04 +0000 https://www.ba0sh1.com/?p=591#comment-67 I found no issues so far using the atmega328 with 2.8 – 3.3V at full 16MHz. In Fact, it is the only reliable way to overclock it to 25MHz without any major temperature increase (At 5V it gets pretty hot/unstable)

At 2.7V the internal watchdog resets the micro, the most common cause for CPU erratic operation, if the supply is not properly decoupled. So if the project is not some crytical application, 3.3V works reasonably well between 12-16MHz.

]]> By: Nico https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-66 Sat, 07 Feb 2015 15:57:07 +0000 https://www.ba0sh1.com/?p=591#comment-66 “the chip is only specified at 10MHz with 3.3V supply” No that is not true! Only at 2,7V you Need to choose 10MHz. Actually the 328P can be driven with 13.3MHz at 3.3V. More common is a 12MHz crystal, which you can get everywhere. Take a look at page 303 in the datasheet.

]]> By: Brody https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-65 Wed, 31 Dec 2014 10:26:06 +0000 https://www.ba0sh1.com/?p=591#comment-65 There is no need to change the Arduino nano to obtain +3.3V levels on the I2C signals.
If you have both 5V and 3.3V I2C busses a level translator can be used.

For a single signal the level translator consists of a MOSFET, such as a BSS138. SOurce to the low level side, drain to the high level side, gate on +3.3V. The best results can be obtained if the transistor is bridged by a schottky diode (e.g. BAT54), drain to cathode, source to anode.

Both sides should have a pull-up resistor, the drain to +5V, the source to +3.3V. The two resistors should not present a load above 3mA! If these resistors are called Rs(ource) and Rd(rain) then 5V/Rd + 3.3V/Rs <=3mA.
This because I2C chips cannot sink more than 3mA.

So in essence you need 2xBS138, 2xBAT54 and two extra resistors and you have your 3.3V I2C interface without any modifications to the Arduino.

Regards,

Brody

]]> By: Baoshi https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-64 Wed, 04 Dec 2013 09:12:06 +0000 https://www.ba0sh1.com/?p=591#comment-64 In reply to Matthieu.

5v is required for FT233RL when internal oscillator is used. So I have to move FT232 power supply to VUSB

]]> By: Matthieu https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-63 Wed, 04 Dec 2013 08:55:13 +0000 https://www.ba0sh1.com/?p=591#comment-63 Sorry, i was not clear enough…
if you change the regulator, it will change all the supply lines, there will be no 5V anymore, nowhere, am i wrong ?
The so-called +5V will become ACTUALLY a +3,3V one !

]]> By: Baoshi https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-62 Tue, 03 Dec 2013 13:30:53 +0000 https://www.ba0sh1.com/?p=591#comment-62 In reply to Matthieu.

If VCCIO is +5V, the RX/TX of FT232 will become 5V as well. I’m not sure if ATMega328p’s RX/TX is 5V tolerant when it is running at 3.3V. So I choose to stay at safer side and use 3.3V I/O.

]]> By: Matthieu https://ba0sh1.com/2013/03/30/tutorial-3-3v-hacking-for-arduino-nano/#comment-61 Tue, 03 Dec 2013 08:19:02 +0000 https://www.ba0sh1.com/?p=591#comment-61 hi thanks for this tuto !
just a question, why do you change the ftdi vccio connection ? In original nano it’s connected to “+5V” bus, which became actually a 3,3V by changing the regulator, so no need to change it ? am i wrong ?
Matthieu

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