DA16200 MQTT operation

Hi tjm,

Thanks for your question and for your interest in our Low-Power Wi-Fi solutions.

Let me check this question and I'll get back to you.

Thanks, PM_Dialog

I have the MQTT working with QOS=0 and QOS=1 using the public broker test.mosquitto,org and the port 1883. I am now trying to get TLS to work (port 8883) since this is a requirement. In the Dialog document um-wi-010-da16200_mqtt_programmer_user_manual_rev_1v3.pdf it shows how to load the 3 certificates and how to start the subscriber using those certificates but I am not sure where I get these certificates. I have downloaded a certificate mosquitto.org.crt from the https://test.mosquitto.org/ site. I believe that is the client certificate. where do I get the root CA and the client key? I appreciate any help you can give since this is a customer requirement that it has TLS capability.

Hi tjm, 

FYI - I have escalated all your questions to our Team internally to check them out. I'll get back to you shortly.

Thanks, PM_Dialog

Hi tjm , 

There is a description of MQTT in DA16200 MQTT Programmer Guide (dialog-semiconductor.com) and  DA16200 AT Command (dialog-semiconductor.com).

And there is an example in samples\Network\MQTT_Client_Sample\ of SDK

Thanks, PM_Dialog

Hi tjm , 

There is an updated MQTT user manual.
https://www.dialog-semiconductor.com/sites/default/files/2021-09/UM-WI-010_DA16200_MQTT_Programmer_Guide_Rev_1v7.pdf

You could test and implement MQTT refer to the above user manual.

• Chapter 5. Test: How to test the MQTT function on the DA16200
• Chapter 4. Sample code: MQTT example code of publisher and subscriber.

Thanks, PM_Dialog

Hi tjm , 

We guide JSON sample code additionally.

DA16200 SDK supports JSON and provides sample code.
The JSON sample code is located in the below SDK directory.

[SDK root]/0.DOC/Doxygen/html/json.html

Can you please let us know if you need any other clarifications? 

Thanks, PM_Dialog

Hi,

I'm kind of in the same situation as you are.from where can we find these 3 certificates.

If you have done it please reply.

Regards 

Prem Sai

Hi premsai,

The following link explains one way to generate the certificates using OpenSSL

https://openest.io/en/services/mqtts-how-to-use-mqtt-with-tls/ 

Please try this and let us know if you have any follow-up questions.

Best regards,
AA_Renesas

Hi,

Thanks for the response.

Curretly i'm trying to test using free mqtt broker

IP:"broker.emqx.io" 

Port:8883

In their website " ">www.emqx.com/.../public-mqtt5-broker" they have provided a CA.

So what i've undertsood is that this Root CA should be loaded to the DA16200 module but how can we create a client certificate as well as client private key from this Root CA.

I'm fairly new to MQTT TLS, Please correct me if i'm wrong.

Regards

Prem Sai

Hi premsai,

The certificate authority (CA) can be used to generate a client certificate. Please refer to the link shared in my previous comment

https://openest.io/en/services/mqtts-how-to-use-mqtt-with-tls/

The steps as described in the shared link are

1) Generating your own certificate authority (CA) using openssl

openssl req -new -x509 -days 365 -extensions v3_ca -keyout ca.key -out ca.crt

2) Creating a private key and a signing request for the broker(server) 

openssl genrsa -out broker.key 2048
openssl req -out broker.csr -key broker.key -new

3) Passing the Certificate signing request to your authority 

openssl x509 -req -in broker.csr -CA ../ca/ca.crt -CAkey ../ca/ca.key -CAcreateserial -out broker.crt -days 100

4) Similar to steps 2 and 3 generate a client private key, signing request and pass the request to your authority

openssl genrsa -out client.key 2048
openssl req -out client.csr -key client.key -new 
openssl x509 -req -in client.csr -CA ../ca/ca.crt -CAkey ../ca/ca.key -CAcreateserial -out client.crt -days 100

After these steps you can transfer the three produced files to the da16200 as described in page 24 of the 

https://www.dialog-semiconductor.com/sites/default/files/2021-12/UM-WI-010_DA16200_DA16600_MQTT_Programmer_Guide_Rev_1v8.pdf 

Certificate authority -> ca.crt
Client certificate -> client.crt
Client key-> client.key

The mqtt broker configuration file will need to be updated accordingly as mentioned in the shared link

— complete mosquitto.conf: —

listener 8883
cafile c:\mqtt\tls\ca\ca.crt
certfile c:\mqtt\tls\broker/broker.crt
keyfile c:\mqtt\tls\broker\broker.key
require_certificate true
use_identity_as_username true

Please follow the instructions and  let us know if you have follow-up questions.

Best regards,
AA_Renesas