Renesas DA16200 PMOD User manual

User Manual
DA16200 DA16600 MQTT
Programmer Guide
UM-WI-010
Abstract
This MQTT Programmer Guide intends to assist software developers that implement applications
with the DA16200 and DA16600 SDK. A certain degree of reader familiarity with programming
environments, debugging tools, and software engineering process in general.

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
2 of 46
© 2023 Renesas Electronics
Contents
Abstract................................................................................................................................................ 1
Contents............................................................................................................................................... 2
Figures.................................................................................................................................................. 3
Tables ................................................................................................................................................... 3
Terms and Definitions......................................................................................................................... 4
References ........................................................................................................................................... 4
1 Overview......................................................................................................................................... 5
2 SDK Build....................................................................................................................................... 5
3 Application Programming Interface ............................................................................................ 6
3.1 Operation APIs...................................................................................................................... 6
3.2 Configuration APIs ................................................................................................................ 7
4 Example Code.............................................................................................................................. 11
4.1 MQTT Publisher..................................................................................................................11
4.2 MQTT Subscriber................................................................................................................ 12
4.3 Receiving/Processing Message (from MQTT Publisher).................................................... 12
4.4 Periodic Message Publishing..............................................................................................13
4.5 Running Sub and Pub at the Same Time (with DPM) ........................................................ 13
4.6 MQTT Client Sample...........................................................................................................14
5 Test............................................................................................................................................... 15
5.1 Test Environment................................................................................................................15
5.2 Setup...................................................................................................................................15
5.3 Publisher ............................................................................................................................. 16
5.3.1 Non-QoS Message .............................................................................................. 16
5.3.2 QoS Message......................................................................................................17
5.3.3 MQTT over TLS...................................................................................................19
5.3.4 Username and Password .................................................................................... 20
5.4 Subscriber...........................................................................................................................21
5.4.1 Setup.................................................................................................................... 21
5.4.2 MQTT over TLS...................................................................................................21
5.4.3 Username and Password .................................................................................... 21
5.4.4 WILL..................................................................................................................... 22
5.5 MQTT Pub/Sub Test with DPM and TLS............................................................................22
5.5.1 MQTT Reconnection Scheme ............................................................................. 24
5.5.2 DPM Power Profile .............................................................................................. 24
5.6 MQTT CleanSession=0 Test Guide.................................................................................... 25
5.6.1 CleanSession=0 Mode ........................................................................................25
5.6.1.1 CleanSession and QoS Matrix Table for PUBLISH Rx ................... 27
5.6.1.2 CleanSession and QoS Matrix Table for PUBLISH Tx....................28
5.6.2 Test steps ............................................................................................................ 29
5.6.2.1 How to connect with CleanSession=0.............................................29
5.6.2.2 How to restart CleanSession=0 test................................................30
5.6.2.3 PUBLISH Rx Test............................................................................ 31

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
3 of 46
© 2023 Renesas Electronics
5.6.2.4 PUBLISH Tx Test ............................................................................36
5.7 Reset...................................................................................................................................37
6 Certificate..................................................................................................................................... 38
6.1 Certificate Commands.........................................................................................................38
6.2 CA, Client Cert, and Client Key...........................................................................................40
Revision History ................................................................................................................................ 44
Figures
Figure 1: MQTT Messaging Concept .................................................................................................... 5
Figure 2: Publish Non-QoS Message.................................................................................................. 16
Figure 3: Publish QoS 1 Message....................................................................................................... 17
Figure 4: Publish QoS 2 Message....................................................................................................... 18
Figure 5: Configure Parameters and Publish a Message ................................................................... 18
Figure 6: Publish Secure Message ..................................................................................................... 19
Figure 7: User Login............................................................................................................................ 20
Figure 8: DPM Sleep after MQTT Connection .................................................................................... 23
Figure 9: MQTT UC Wakeup............................................................................................................... 23
Figure 10: MQTT Wakeup for Sending Message................................................................................ 24
Figure 11: MQTT Communication....................................................................................................... 25
Figure 12: Broker console - CleanSession=1 connection................................................................... 26
Figure 13: Broker console - CleanSession=0 connection................................................................... 26
Tables
Table 1: MQTT API List......................................................................................................................... 6
Table 2: Configuration API .................................................................................................................... 7
Table 3: MQTT Messaging Configuration (String Type) ....................................................................... 8
Table 4: MQTT Messaging Configuration (Integer Type)...................................................................... 9
Table 5 CleanSession and QoS matrix in message Rx ...................................................................... 28
Table 6 CleanSession and QoS matrix in message Tx....................................................................... 28

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
4 of 46
© 2023 Renesas Electronics
Terms and Definitions
MQTT Message Queuing Telemetry Transport
DPM Dynamic Power Management
TCP Transmission Control Protocol
UDP User Datagram Protocol
API Application Programming Interface
AP Access Point
QoS Quality of Service
TLS Transport Layer Security
References
[1] DA16200, Datasheet, Renesas Electronics
[2] DA16200 DA16600, SDK Programmer Guide, Renesas Electronics
[3] DA16200 DA16600, FreeRTOS Example Application Manual

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
5 of 46
© 2023 Renesas Electronics
1 Overview
MQTT (Message Queue Telemetry Transport) is an ISO standard (ISO/IEC PRF 20922) publish-
subscribe-based messaging protocol. It works on top of the TCP/IP protocol. The publisher sends
(PUBLISH) messages to the subscriber through the broker. The subscriber needs to keep the
connection with the broker by TCP session while the publisher can disconnect the session with the
broker after sending a message.
As shown in Figure 1, once the broker receives a message with a specific topic the message is sent
to subscribers that already registered with the topic. A subscriber can register with more than one
topic. There can be many or no subscribers which registered with a specific topic.
Figure 1: MQTT Messaging Concept
The exchange of MQTT messages supports QoS (Quality of Service). QoS has three levels (0, 1,
and 2) and the process of each QoS level is as below.
The DA16200 (DA16600) supports both publisher and subscriber functions and allows simultaneous
use. The subscriber function supports DPM mode. TLS is available for message encryption.
2 SDK Build
Some source files should be modified in the DA16200 (DA16600) SDK to use the MQTT function.
Enable the MQTT function as shown in the example below.
config_generic_sdk.h
...
#define __SUPPORT_MQTT__ // Support MQTT

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
6 of 46
© 2023 Renesas Electronics
3 Application Programming Interface
3.1 Operation APIs
The APIs listed in Table 1 are used to create or terminate the MQTT thread, to check the status, and
to publish a message. The configuration to execute MQTT protocols is explained in the next section.
Table 1: MQTT API List
int mqtt_client_start(void)
Return
If succeeded, returns 0. If failed, returns an error code.
Description
Create the MQTT client thread.
int mqtt_client_stop(void)
Return
If succeeded, returns 0. If there is no thread to terminate, returns -1.
Description
Terminate the MQTT client thread.
int mqtt_client_check_conn(void)
Return
1 (true): Connected to a broker.
0 (false): Not connected.
Description
Check whether the MQTT session is connected.
int mqtt_client_send_message(char *top, char *publish)
Return
0: Succeeded to publish.
-1: Failed because mqtt is not connected.
-2: Failed because the previous message send is in progress.
-3: Failed because mqtt topic is missing.
Other: Failed due to other cause. See enum “mqtt_client_error_code”to identify
the cause.
Parameter
top
Topic (if NULL, the MQTT publisher sends a PUBLISH message with the topic
stored in NVRAM.)
publish
Message to be published.
Description
Publisher sends an MQTT message (PUBLISH).
int mqtt_client_send_message_with_qos(char *top, char *publish, timeout)
Return
0: Succeeded to publish.
-1: Failed to publish because Publisher is not ready to send.
-2: Failed to publish because the timeout expired.
Parameter
top
Topic (if NULL, the MQTT module sends a PUBLISH message with the topic
stored in NVRAM.)
publish
Message to be published.
timeout
Timeout to wait for a previous QoS message to process completely (unit:
10 ms).
Description
Publisher sends an MQTT message (PUBLISH) with a timeout check.

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
7 of 46
© 2023 Renesas Electronics
int mqtt_client_unsub_topic(char *topic)
Return
0: Succeeded to unsubscribe.
4: Failed because mqtt is not connected.
3: Failed because the topic is NULL
1: Failed because of memory alloc failure
Other: Failed due to other cause. See enum “mqtt_client_error_code” to identify
the cause.
Parameter
topic
Topic to unsubscribe
Description
Unsubscribe from the topic specified.
Invoke this function only when mqtt client is in a connected state with Broker.
3.2 Configuration APIs
With NVRAM items, the user can configure MQTT messaging. This allows configuring the publisher
and the subscriber.
Table 2: Configuration API
int mqtt_client_config_initialize(void)
Return
If succeeded, returns 0 (MOSQ_ERR_SUCCESS. If failed, returns an error
code.
Description
Reset all MQTT Configurations.
void mqtt_sub_callback_set(void (*user_cb)(void))
Return
None
Parameter
user_cb
user callback function to set
Description
Register a callback function that is invoked when a MQTT Subscriber is
connected with a Broker.
void mqtt_pub_callback_set(void (*user_cb)(void))
Return
None
Parameter
user_cb
user callback function to set
Description
Register a callback function that is invoked when publishing a message is done
void mqtt_msg_callback_set(void (*user_cb)(const char *buf, int len, const char *topic))
Return
None
Parameter
user_cb
user callback function to set
buf: PUBLISH message received
len: PUBLISH message length
topic: the topic of the PUBLISH message received
Description
Register a callback function that is invoked when a PUBLISH message arrives.

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
8 of 46
© 2023 Renesas Electronics
void mqtt_sub_disconn_cb_set(void (*user_cb)(void));
Return
None
Parameter
user_cb
user callback function to set
Description
Register a callback function that is invoked when the MQTT client is
disconnected
void mqtt_sub_disconn2_cb_set(void (*user_cb)(void));
Return
None
Parameter
user_cb
user callback function to set
Description
- Register callback function called when MQTT Subscriber is disconnected by
receiving a message with invalid unsupported length if the connection is
clean_session=0 and qos > 0.
- On receipt of this callback, application needs to clear the message in Broker
by connecting with clean_sesion=1.
- To use this API, __MQTT_CLEAN_SESSION_MODE_SUPPORT__ should
be enabled.
void mqtt_subscribe_callback_set(void (*user_cb)(void));
Return
None
Parameter
user_cb
user callback function to set
Description
Register a callback function that is invoked when a SUBSCRIBE request to a
topic is finished
void mqtt_unsubscribe_callback_set(void (*user_cb)(void));
Return
None
Parameter
user_cb
user callback function to set
Description
Register a callback function that is invoked when an UNSUBSCRIBE request is
finished
Table 3: MQTT Messaging Configuration (String Type)
Name
Description
Example
DA16X_CONF_STR_MQTT_BROKER_IP
Broker IP address (or
URI).
da16x_set_config_str(DA16X_CONF_STR
_MQTT_BROKER_IP, “192.168.0.1”);
DA16X_CONF_STR_MQTT_SUB_TOPIC
Subscriber topic
(previous topics will
be removed).
da16x_set_config_str(DA16X_CONF_STR
_MQTT_SUB_TOPIC, topic);
DA16X_CONF_STR_MQTT_SUB_TOPIC_ADD
Subscriber topic to
add (up to four).
da16x_set_config_str(DA16X_CONF_STR
_MQTT_SUB_TOPIC_ADD, topic);

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
9 of 46
© 2023 Renesas Electronics
Name
Description
Example
DA16X_CONF_STR_MQTT_SUB_TOPIC_DEL
Subscriber topic to
remove.
da16x_set_config_str(DA16X_CONF_STR
_MQTT_SUB_TOPIC_DEL, topic);
DA16X_CONF_STR_MQTT_PUB_TOPIC
Topic to publish.
da16x_set_config_str(DA16X_CONF_STR
_MQTT_PUB_PUB_TOPIC, “pub_topic”);
DA16X_CONF_STR_MQTT_USERNAME
Username to log in to
a broker.
da16x_set_config_str(DA16X_CONF_STR
_MQTT_USERNAME, “mqtt_id”);
DA16X_CONF_STR_MQTT_PASSWORD
Password to login to a
broker.
da16x_set_config_str(DA16X_CONF_STR
_MQTT_PASSWORD, “mqtt_password”);
DA16X_CONF_STR_MQTT_WILL_TOPIC
Will Topic.
da16x_set_config_str(DA16X_CONF_STR
_MQTT_WILL_TOPIC, “will_topic”);
DA16X_CONF_STR_MQTT_WILL_MSG
Will Message.
da16x_set_config_str(DA16X_CONF_STR
_MQTT_WILL_MSG, “will_msg”);
DA16X_CONF_STR_MQTT_SUB_CLIENT_ID
MQTT client ID.
da16x_set_config_str(DA16X_CONF_STR
_MQTT_SUB_CLIENT_ID, “sub_id”);
DA16X_CONF_STR_MQTT_TLS_SNI
MQTT TLS SNI
(Server Name
Indication)
da16x_set_config_str(DA16X_CONF_STR
_MQTT_TLS_SNI, “sni_str”)
Note 1 Up to four subscriber topics can be registered, and only one publisher topic can be registered.
Table 4: MQTT Messaging Configuration (Integer Type)
Name
Description
Example
DA16X_CONF_INT_MQTT_SUB
MQTT operation
(0: stop, 1: start).
da16x_set_config_int(DA16X_CONF_INT
_MQTT_SUB, 1);
DA16X_CONF_INT_MQTT_AUTO
MQTT Auto-start at
booting system
(0: disable, 1: enable).
da16x_set_config_int(DA16X_CONF_INT
_MQTT_AUTO, 1);
DA16X_CONF_INT_MQTT_PORT
Broker port number.
da16x_set_config_int(DA16X_CONF_INT
_MQTT_PORT, 8883);
DA16X_CONF_INT_MQTT_QOS
QoS level (0~2).
da16x_set_config_int(DA16X_CONF_INT
_MQTT_QOS, 2);
DA16X_CONF_INT_MQTT_TLS
TLS (0: disable, 1:
enable).
da16x_set_config_int(DA16X_CONF_INT
_MQTT_TLS, 1);
DA16X_CONF_INT_MQTT_WILL_QOS
QoS level of will
messages (0~2).
da16x_set_config_int(DA16X_CONF_INT
_MQTT_WILL_QOS, 1);
DA16X_CONF_INT_MQTT_PING_PERIOD
MQTT ping period
(secs).
da16x_set_config_int(DA16X_CONF_INT
_MQTT_PING_PERIOD, 86400);
DA16X_CONF_INT_MQTT_VER311
MQTT protocol :
1 (v3.1.1) / 0 (v3.1)
da16x_set_config_int(DA16X_CONF_INT
_MQTT_VER311, 1)
DA16X_CONF_INT_MQTT_TLS_INCOMING
TLS incoming buffer
size: default (1024*4),
min (1024*2), max
(1024*8)
da16x_set_config_int(DA16X_CONF_INT
_MQTT_TLS_INCOMING, 1024*4)
DA16X_CONF_INT_MQTT_TLS_OUTGOING
TLS outgoing buffer
size: default (1024*4),
min (1024*2), max
(1024*8)
da16x_set_config_int(DA16X_CONF_INT
_MQTT_TLS_OUTGOING, 1024*4)

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
10 of 46
© 2023 Renesas Electronics
Name
Description
Example
DA16X_CONF_INT_MQTT_TLS_AUTHMODE
TLS peer certificate
verification mode: 0
(not verify), 1
(optional), 2 (required),
default is 1
da16x_set_config_int(DA16X_CONF_INT
_MQTT_TLS_AUTHMODE, 1)
DA16X_CONF_INT_MQTT_CLEAN_SESSION
MQTT Clean Session
mode (1: clean the
previous session, 0: do
not clean the previous
session)
da16x_set_config_int(DA16X_CONF_INT
_MQTT_CLEAN_SESSION, 1);

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
11 of 46
© 2023 Renesas Electronics
4 Example Code
DA16200 (DA16600) MQTT publisher and subscriber are configured by NVRAM items. Once all
configurations are done, you just need to run the subscriber thread or publish an MQTT message.
4.1 MQTT Publisher
Set the configurations for the MQTT broker, publisher topic, and so on when executing power on
reset or requiring new MQTT configuration. Call mqtt_client_start() and mqtt_client_send_message()
with a message, then DA16200 (DA16600) will temporarily connect to the broker and publish the
message.
#include "mqtt_client.h"
#include "common_config.h"
int mqtt_pub_example(void)
{
int status;
char send_msg[16] = {0, };
int wait_cnt = 0;
strcpy(send_msg, "Hello broker.");
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_BROKER_IP, "172.16.0.1");
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_PORT, 1884);
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_PUB_TOPIC, "da16k_pub");
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_USERNAME, "username");
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_PASSWORD, "password");
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_QOS, 0);
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_TLS, 0);
da16x_nvcache2flash();
status = mqtt_client_start();
if (status) {
PRINTF("Failed to initialize MQTT Client.\n");
return status;
}
...
while (1) {
if (!mqtt_client_check_conn()) {
vTaskDelay(100);
wait_cnt++;
if (wait_cnt == 10) { // 10 sec for example …
PRINTF("mqtt connection timeout!, check your configuration \n");
return -1;
}
} else {
break;
}
}
...
mqtt_client_send_message(NULL, send_msg);
...

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
12 of 46
© 2023 Renesas Electronics
}
4.2 MQTT Subscriber
Set the configurations for the MQTT broker, subscriber topic, and so on before running the
subscriber thread. Call mqtt_client_start() and then the subscriber thread will start.
#include "mqtt_client.h"
#include "common_config.h"
int mqtt_sub_example(void)
{
int status;
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_BROKER_IP, "172.16.0.1");
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_PORT, 1884);
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_SUB_TOPIC, "da16k_sub");
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_USERNAME, "username");
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_PASSWORD, "password");
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_QOS, 0);
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_TLS, 0);
da16x_nvcache2flash();
status = mqtt_client_start();
return status;
}
4.3 Receiving/Processing Message (from MQTT Publisher)
MQTT receives messages via a callback and a user needs to register this callback function. To be
able to add a callback, Section 4.2 should be done first (file mqtt_client.h should be included).
mqtt_client_set_msg_cb(mqtt_msg_cb);
NOTE
The user thread that registers a message callback should have the same or higher priority than the
“mqtt_client” thread (the priority of the mqtt_client thread is currently USER_PRI_APP(1)) for mqtt_client to be
able to register the user callback before MQTT initialization.
The following example code shows a callback sample implementation. In this implementation, when
a message is received, and if the payload is “1”, a certain message is printed just like one in the box
below.
static void mqtt_msg_cb(const char *buf, int len, const char *topic)
{
if (strncmp(message->payload, "1", 1) == 0) {
char msg[64] = {0, };
sprintf(msg, "DA16X status: Not bad (%d)", ++mqtt_sample_msg_id);
PRINTF("msg: %s \n", msg);
...
}
}

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
13 of 46
© 2023 Renesas Electronics
4.4 Periodic Message Publishing
When an MQTT Publisher session is connected, you can register a timer for publishing a periodic
message. To be notified of Publish complete, you should call the callback API as below.
mqtt_pub_callback_set(mqtt_pub_cb);
After MQTT Publisher is connected, you can register a RTC timer (in DPM mode) or RTOS timer (in
non-DPM mode). Below is an example of RTC timer.
#define MQTT_PUB_MSG_PERIODIC 30 // secs
static void mqtt_connected_cb(void)
{
if (!dpm_mode_is_wakeup()) {
dpm_timer_create(SAMPLE_MQTT_CLIENT, "timer1", mqtt_pub_send_periodic,
MQTT_PUB_MSG_PERIODIC, MQTT_PUB_MSG_PERIODIC);
}
}
In DPM mode, for a periodic RTC timer registration, it is registered normally on Power-On-Boot. That
means, when the RTC timer is expired, DA16200 wakes up, the callback invoked, and a message is
printed on the console as below.
static void mqtt_pub_send_periodic(char *timer_name)
{
…
// inform worker_thread
xEventGroupSetBits(evt_grp, EVT_PUBLISH);
…
}
…
Static void worker_thread(void)
{
…
xEventGroupWaitBits(evt_grp, …);
…
if (events &EVT_PUBLISH) {
char msg[64] = {0, };
…
strcpy(msg, "DA16K Periodic Message");
mqtt_client_send_message(NULL, msg);
} else {
…
}
…
}
4.5 Running Sub and Pub at the Same Time (with DPM)
void cmd_mqtt_sample(int argc, char *argv[])
{
/* Wi-Fi Connection Setting */
da16x_set_nvcache_int(DA16X_CONF_INT_MODE, 0);
da16x_set_nvcache_str(DA16X_CONF_STR_SSID_0, "TEST_AP");
da16x_set_nvcache_int(DA16X_CONF_INT_AUTH_MODE_0, CC_VAL_AUTH_WPA2);
da16x_set_nvcache_int(DA16X_CONF_INT_ENCRYPTION_0, CC_VAL_ENC_CCMP);
da16x_set_nvcache_str(DA16X_CONF_STR_PSK_0, “12345678”);

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
14 of 46
© 2023 Renesas Electronics
/* MQTT Setting */
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_AUTO, 1);
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_BROKER_IP, "172.16.0.1");
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_PORT, 8883);
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_QOS, 0);
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_TLS, 1);
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_SUB_TOPIC, "da16k");
da16x_set_nvcache_str(DA16X_CONF_STR_MQTT_PUB_TOPIC, "da16k_sub");
da16x_set_nvcache_int(DA16X_CONF_INT_MQTT_PING_PERIOD, 60);
/* DPM after Rebooting */
da16x_set_nvcache_int(DA16X_CONF_INT_DPM, 1);
/* Enabled SNTP for TLS */
da16x_set_nvcache_int(DA16X_CONF_INT_SNTP_CLIENT, 1);
da16x_nvcache2flash();
/* Input Certificate & Private Key */
cert_flash_write(SFLASH_ROOT_CA_ADDR1, (char*)cert_buffer0,
strlen(cert_buffer0));
cert_flash_write(SFLASH_CERTIFICATE_ADDR1, (char*)cert_buffer1,
strlen(cert_buffer1));
cert_flash_write(SFLASH_PRIVATE_KEY_ADDR1, (char*)cert_buffer2,
strlen(cert_buffer2));
reboot_func(SYS_REBOOT, DISCONNECT_SEND);
}
4.6 MQTT Client Sample
MQTT client sample can be found in [SDK_ROOT/apps/common/examples/
Network/MQTT_Client/src/mqtt_client_sample.c].
This simple application demonstrates receiving and sending an MQTT message.
For sample guide, see DA16200 DA16600, FreeRTOS Example Application Manual.

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
15 of 46
© 2023 Renesas Electronics
5 Test
This section explains how to test the MQTT function on the DA16200 (DA16600) debug console
window.
5.1 Test Environment
For this test the mosquitto MQTT broker is used, which you can download from the following URL:
https://mosquitto.org/download/
If you feel that the broker installation is difficult, Renesas Electronics can provide it so that you can
extract and run it on your Windows PC.
5.2 Setup
Open a command window and go to the mosquitto folder.
1. Run a broker.
mosquitto -v -p <Port Number>
2. Open a new command window and run a subscriber.
mosquitto_sub -h <Broker IP> -p <Port Number> -t <Topic>
The following message is shown in the broker window.
3. Open a new command window and publish a message.
mosquitto_pub -h <Broker IP> -p <Port Number> -t <Topic> -m "<Message>"

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
16 of 46
© 2023 Renesas Electronics
The following message is shown in the broker window.
The subscriber receives the message.
5.3 Publisher
5.3.1 Non-QoS Message
This section gives an example of publishing a non-QoS message.
Figure 2: Publish Non-QoS Message
1. After the DA16200 (DA16600) EVB is connected to an AP, configure the parameters and publish
a message.
[/DA16200]# net
[/DA16200/NET]# mqtt_config broker <Broker IP>
[/DA16200/NET]# mqtt_config port <Port Number>
[/DA16200/NET]# mqtt_config pub_topic <Topic>
[/DA16200/NET]# mqtt_client start
>>> MQTT Client connection OK (da16x_FFFE)
[/DA16200/NET]# mqtt_client -m <Message>
…
[/DA16200/NET]# mqtt_client stop
Optionally, “client_id”can also be set with the following command:
[/DA16200/NET]# mqtt_config client_id <client_id_string>
For example, mqtt_config client_id abcd1111
client_id should be unique per each device. By default, client_id is generated internally like
“da16x_<the last 2 bytes of mac address>”. For example, da16x_FCFA.

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
17 of 46
© 2023 Renesas Electronics
2. When message transmission -m “Hello!”is successful, you can see the following messages:
Hello! (Send, Len: 6, Topic: da16k, Message ID: 1)The following syntax allows to send a
message with a new topic:
[/DA16200/NET] mqtt_client -m <Message> <NewTopic>
If the previous parameters for broker, port, and topics are not changed, then you do not need to set
the parameters for the publication of every message.
* The max length of the console command is 158. To send a longer PUBLISH, write the following
command:
[/DA16200/NET] mqtt_client -l
Typing data: (MQTT Publisher message)
Cancel - CTRL+D, End of Input - CTRL+C or CTRL+Z
1234567890123456789012345678901234567890123456789012345678901234567890123456789012
3456789012345678901234567890123456789012345678901234567890123456789012345678901234
5678901234567890123456789012345678901234567890123456789012345678901234567890123456
7890 …
Use the keyboard combinations Ctrl+C or Ctrl+Z to send the message.
5.3.2 QoS Message
This section gives an example of publishing a QoS message.
Figure 3: Publish QoS 1 Message

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
18 of 46
© 2023 Renesas Electronics
Figure 4: Publish QoS 2 Message
●Configure the parameters and publish a message.
[/DA16200/NET]# mqtt_config broker <Broker IP>
[/DA16200/NET]# mqtt_config port <Port Number>
[/DA16200/NET]# mqtt_config pub_topic <Topic>
[/DA16200/NET]# mqtt_config qos <QoS Level>
[/DA16200/NET]# mqtt_client start
>>> MQTT Client connection OK (da16x_FFFE)
[/DA16200/NET]# mqtt_client -m <Message>
Figure 5: Configure Parameters and Publish a Message

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
19 of 46
© 2023 Renesas Electronics
5.3.3 MQTT over TLS
The DA16200 (DA16600) SDK provides a TLS encrypted session for secure MQTT messages.
Figure 6: Publish Secure Message
NOTE
You need to store certificates in the DA16200 (DA16600) EVK to use TLS encryption. This procedure is
explained in Section 6.
1. Run a broker with a secure port.
mosquitto –c mosquitto.conf -p <Port Number> -v
2. Run a subscriber.
mosquitto_sub -h <Broker IP> -p <Port> --cafile <CA Certificate> --cert <Client
Certificate> --key <Client Private Key> --tls-version <TLS Protocol Version> --
insecure -t <Topic>
3. Set the current time in the DA16200 (DA16600) EVB to check if the certificate is valid.
(If you want to use SNTP for time sync, input the command “net.sntp enable”to get the current
time.)
[/DA16200]# time set <yyyy-mm-dd> <hh:mm:ss>
4. Store three Certificates (see Section 6.1) in the DUT, and then follow the steps below.
[/DA16200/NET]# mqtt_config broker <Broker IP>
[/DA16200/NET]# mqtt_config port <Port Number>
[/DA16200/NET]# mqtt_config pub_topic <Topic>
[/DA16200/NET]# mqtt_config tls 1
[/DA16200/NET]# mqtt_client start
>>> MQTT Client connection OK (da16x_FFFE)
[/DA16200/NET]# mqtt_client -m <Message>

UM-WI-010
DA16200 DA16600 MQTT Programmer Guide
User Manual
Revision 1.12
18-Jan-2023
CFR0012
20 of 46
© 2023 Renesas Electronics
5.3.4 Username and Password
1. Set up a username and password to authenticate users.
Figure 7: User Login
2. Run a broker with a secure port. You need to prepare the configuration file.
mosquitto -c <Config File> -p <Port> -v
In the mosquitto package provided by Renesas Electronics, file mosq_idpw.conf is used for the
<Config File> parameter, and user accounts are registered in file p1.txt.
3. You can add a new account in this file with the following command:
mosquitto_passwd.exe -b p1.txt <username> <password>
4. At the mosquitto command prompt, please run the mosquito_sub command to log in successfully
to the broker.
mosquitto_sub -h <broker_ip> -p <port> -t <topic> -u <id> -P <pass>
5. On mqtt_client (DUT), set the username and password, and start mqtt_client.
[/DA16200/NET]# mqtt_config broker <Broker IP>
[/DA16200/NET]# mqtt_config port <Port Number>
[/DA16200/NET]# mqtt_config pub_topic <Topic>
[/DA16200/NET]# mqtt_config tls 0
[/DA16200/NET]# mqtt_config username <Username>
[/DA16200/NET]# mqtt_config password <Password>
[/DA16200/NET]# mqtt_client start
>>> MQTT Client connection OK (da16x_FFFE)
[/DA16200/NET]# mqtt_client -m <Message>
NOTE
●The max length of the console command is 158 so to type in a password exceeding the limit of the
console, use the command “mqtt_config long_password”
●The max length of the buffer is currently 160 for a password, 64 for a username. If you want to change
max length, modify MQTT_USERNAME_MAX_LEN or MQTT_PASSWORD_MAX_LEN, if required