Hi, 

I'm currently attempting to wake the Whisper Node using the alarm2 interrupt on the RS3231. I have tried without connecting and then eventually connected JP11 and still had no luck with waking the node. I was hoping the simply having the alarm trigger an interrupt would wake the device however that did not work out. I have tested the connections on the RS3231 and they are all working fine and I can log times fine. I can also get the alarms to trigger when the device is awake so I must be missing some small detail here. Any help would be greatly appreciated or ff you had any working examples that I could test then that would be a massive help to me. 

Thanks, 
Liam  

Hi Liam,

I'll try to build a example for that. Meanwhile I would suggest follow the steps:

1. Make sure the JP11 is connecting the DS3231 pin 3 to the D3 port (https://datasheets.maximintegrated.com/ ... S3231M.pdf). You can use a multimeter to make sure the path is fine
2. Set D3 as INPUT with Pull-up - The RTC interrupt is an open-drain, so it needs to have a pull-up
3. Do not use Interrupt at the start, just make a "readPin" and Print it every second.

Basically, you should read the D3 PIN as HIGH at the start because of the pull-up. Once the RTC issues an interrupt it'll "drain" the pull-up and the D3 will read LOW.

I still need to double check the DS3231 specification, but it's very likely you'll need to clear the Interrupt on the RTC, otherwise the D3 will be LOW forever.

If the test above works, you can try to attache the Interrupt (INT1) as a Falling, because the D3 level will change from HIGH to LOW.

Hi thanks for the reply,

I gave these steps a shot and I discovered that I had not flipped the interrupt control bit and I had a delay in my loop which was causing me to miss the serial output. 
Thanks for the advice I would have still been stuck without it. 

Liam 

Are you able to share your sketch and pin layout for sleeping whispernode  and waking via ds3231. I am about to start my investigations and experimentations on this and would appreciate any (time saving) guidance. Cheers.  Nick

Hi Nick, if you're using the Whisper Node LoRa with the DS3231 chip onboard you will need to add a jumper, the JP11, to the board.

The JP11 will link the INT/SQW DS3231 pin to the D3 MCU pin (the D3 is the INT1). After that, you can configure the DS3231 to send alarms or square waves to that pin and configure the MCU to respond to it or wake-up.

As far I remember the INT/SQW is an open-drain, but there's a 100K pull-up already there. So you basically need to configure your interrupt to be triggered on "falling edge".

Finally, if you are using the D3 already or wishes to connect the DS3231 interrupt to another pin you can use the Header P6, position2 (centre) and wire it to any other MCU IO. Attached the DS3231 schematic for your reference.

Cheers, Mike.

Thanks Mike,
Your response encouraged me to examine the board more closely. Do you sell an edition of the board with the ds3231 attached?
Nick

Hi Nick,

No we only see the DS3231 kit for the user to solder into the whisper node. We can only customise for larger orders over 100 units.

If you're using an external DS3231 module you can simply connect the I2C and INT pins as per the schematic image.