I was watching Talk2 video on unboxing the board ( and here, he says the board doesn't mind 3.3V or 5V from the FTDI port. However, I found conflicting information from bitbucket under the "Programming Interfaces ISP - P3 and FTDI - P4" section. It says, "It's important to note that although the MCU is 5V compatible the Radio Module RFM69 and the Flash SPI memory chip are not. For that reason never connect a 5V ISP programmer to the board or it might damage those components.".

I have a 5V FTDI programmer (https://www.sparkfun.com/products/9716) and I am hesitant to connect it to the board. Will my Whisper Node be alright using this programmer?

Hi aholwi00,

Thanks for spotting that. The documentation on Bitbucket is a bit out-of-date. Connecting a 5V FTDI shouldn't be a problem as the VCC from the FTDI will be regulated by the LDO. Also the 5V TX signal from the FTDI should only "touch" the RX pin of the Whisper Node, being ok to use as the current should be very small.

Saying that, the ideal and safest FTDI adapter would be one providing 5V as supply voltage but having TX and RX levels at 3.3V.

Great! Thank you!

Talk2 wrote: Hi aholwi00,

Thanks for spotting that. The documentation on Bitbucket is a bit out-of-date. Connecting a 5V FTDI shouldn't be a problem as the VCC from the FTDI will be regulated by the LDO. Also the 5V TX signal from the FTDI should only "touch" the RX pin of the Whisper Node, being ok to use as the current should be very small.

Saying that, the ideal and safest FTDI adapter would be one providing 5V as supply voltage but having TX and RX levels at 3.3V.

So with version 1.0 board (compared to 0.3v) I'm running into issues with the FTDI's I have.  If I have it set at 3.3v it is 3.5v VIN, 3.5V RX, 3.1V TX, and with this the board fails to power up (more below).  This same FTDI worked on the 0.3V board.  If I set the FTDI at 5V I get 5V VIN, 5V RW, 4.6V TX, and I haven't tried this on the whisper node as I didn't want to risk frying it based on the github info and not exactly sure even looking at this thread if I should.

Happy to order a different FTDI, there are a few linked around the forums, but what I'm seeing when I have it setup on 3.3V is:
Board doesn't power up (no LEDs)
If I measure voltage on the 3.3V rail of the whisper node, I get 1.5V out (may ahve to do with only 3.1V going in on RX?

If power up with usb I get 3.3V on the 3.3 rail as expected.

Should it be safe to try to power up with just the 5V FTDI one based on the RX/TX voltages mentioned, or do I need to power up with a battery or USB on top of the FTDI instead?

Thoughts?

Hello,

The 0.3 Whisper Node was able to run with 3.3V via VIN (same power input used by the FTDI port).

Now on version 1.0, there's a voltage monitor which will block the VIN if under 3.4V.

Saying that, it's safe to use a 5V FTDI to program the Whisper Node. We've tested and even the TX and RX lines getting 5V the other MCU pins still at the correct voltage levels.

The only concern is if you wish to connect a 5V ISP, as this can damage the radio e flash memory because the ISP uses the same SPI pins as those components.

perfect, as I'm not using the ISP shouldn't be an issue!

Though for now, since I'm programming both the 0.3's and the 1.0's I'll stick to 3.3v and just power it up off battery when I need to program it (that worked great, just tested that after finding the other thread on this in general:  can-t-get-whisper-node-to-work-t56.html)

Thanks!

Glad that i saw this because i thought my newly ordered nodes are not working. i was using 3.3v for ftdi as i did with the previous version

Here the board diagram with the supported voltages for each kind of input, I normally keep a printed copy on my desk as quick reference:

Since the image link is broken would you mind reuploading it ?

Thanks!

You also can find the board diagram image on the product page: https://wisen.com.au/store/products/whisper-node-lora/