LoRa RFM95

Projects General Guidance
1

Hello there, I recently received my logic converter as you suggested me and I plugged everything back in ( see pictures, the links, can't manage to display pictures when I send them from my pc : http://imgur.com/gallery/1B7qWgt ).
Now I tried powering all this without burning the chip and after uploading the serial monitor showed me this:

0
init failed
sending message

(I'm using the Radiohead library )
I don't think it's normal that even if the init failed, the message is still sent
What could it be ?
I've searched in the library and can't find why the init returns false.

Also I modified the line rf95.waitPacketSent(); and added 9 seconds of delay and the other instructions unlocked after 9 seconds,
said there was no server online ( which is normal )
then tried to send another message but blocked again.
( Don't mind the Serial.print("Data" / "Driver ") those were just tests to see where the code stops )

Could you please help me ?
Also don't hesitate to use simple terms etc, I'm french and it would be better for me to understand all this
Thanks

rf95_client.ino (2.64 KB)

2

Oh also I noticed I might run out of logic converters,
There are 5 digital outputs per RF M95 and I have a total of 8 digital converters
Is there a way to avoid using one of these outputs ?
Or convert them myself with resistors ?

3

Staren:
I don't think it's normal that even if the init failed, the message is still sent
What could it be ?
I've searched in the library and can't find why the init returns false.

The init writes to one of the LoRa devices registers and then reads it back, if this fails you get the init failed message.

So as before, you either have it wired wrong, the LoRa device is faulty or there is a problem with the Arduino.

4

Regarding the wiring,
It's: (Arduino side ---> Chip side )
DiO 13 ---> SCK
DiO 12 ---> MISO
DiO 11 ---> MOSI
DiO 10 ---> NSS
DiO 2 ---> DIO0
3.3V ---> 3.3V
GND ---> GND

I may have burned the chip the last time.
Should I try with another one with this wiring setup ?

5

If the wiring is correct, and the Arduino is OK then all you can really do is;

Try another RFM95
Try another SPI device, to check if the Arduino is OK.

6

Okay, thanks for your answers !
I'm gonna use another RF M95 and if this new one isn't initializing either I'll quintuple-check the wiring

7

Hello again,
So I tried wih the other chip ( never used it ) and it's doing exactly the same thing (Init failed then sending then no server found the re sending then nothing )

So in that case I guess the only solution is the wiring but again I connected everything at the right place
Anyone has an idea ?
Thanks

8

Staren:
Anyone has an idea ?

Connect to a proper 3.3V device such as a £1.50 3.3V Arduino Pro Mini.

If it fails init, there is no device found, see #2 for the reasons why this may be.

9

srnet:
Connect to a proper 3.3V device such as a £1.50 3.3V Arduino Pro Mini.

If it fails init, there is no device found, see #2 for the reasons why this may be.

I use logic converters so the voltage is at 3.3V instead of 5V
What's #2 ?

10

Staren:
I use logic converters so the voltage is at 3.3V instead of 5V

Have you used a scope to check the levels and edges on both sides of the logic converter ?

What's #2 ?

Post 2 in this thread.

11

Oh the message number 2 my bad
I'd like to share the wiring again but I don't think it comes from that, and my arduino is okay with other chips

It'd be bad if both Rfm95 chips from the same pack are faulty

12

srnet:
Have you used a scope to check the levels and edges on both sides of the logic converter ?

Post 2 in this thread.

I don't get the first sentence, what do you mean ?

I noticed something stupid, I thought as I already had the chip plugged to the arduino I didn't need to plug the logic converter with the GND, 5V and 3.3V wires

Now it still fails the init but I don't get 0 at the beginning, I'm getting "FF"

13

I noticed something stupid

Since you can't seem to avoid making mistakes, get a 3.3V Arduino and some new radio chips.

14

I won't learn how to get rid of those mistakes though.
By the way I think my arduino IS able to deliver 3.3V because there's a 3.3V port, but on my last topic I've been told I HAD to use these logic converters even with this arduino
Any hint ?
Was it false ?

15

Staren:
I don't get the first sentence, what do you mean ?

If you had used a scope to check the signals either side of the logic level converter its likley there would of been an indication of a problem, the logic converter could have been faulty, not good enough or it could have been miss-wired.

Re-read #7.

16

Staren:
By the way I think my arduino IS able to deliver 3.3V

Its not able to deal (correctly) with 3.3V logic levels, why do you think you were advised to use a logic level converter ?

When I started in microprocessor design back in 1979, most everything was 5V logic (or -5V & +12V but thats another story) and life was a lot easier.

17

but on my last topic I've been told I HAD to use these logic converters even with this arduino

Correct, if you insist on using a 5V Arduino (despite the fact that it has a 3.3V POWER output).

18

Sorry for the late answer I didn't see there was a second page on my topic.
I still don't have any 3.3V board but I'll try again with the 5V and the logical converters until I manage to make the chip work / until I receive my 3.3V board
I'll try with the first chip though, I don't want to break the second and I still don't know if I broke the first

19

So until now with both RFM95 when I plug the logical converters the eror is:
FF
Init failed
Sending to the server

And when I remove the logical converter ( from the chip I'm supposed to have broken ) I get the qame error but with a 0 replacing the FF

I guess it's the same with the brand new one but since the error changes I guess my first chip isn't broken
I checked and FF means 255 in decimal so maybe my chip's sending a full byte of data then init fails I don't know why

20

Staren:
I checked and FF means 255 in decimal so maybe my chip's sending a full byte of data

More likely the LoRa device is not responding at all, and 0xFF is caused by a MOSI pin that has nothing connected to it on the other side of the logic level converter.