Hi,
I need to read the data from an acceleration sensor. I tried with a custom program of mine to simulate some data, but it is delaying too much.
I tried reducing the notification interval, but sometimes it just jumps numbers so to say, it should show 1,2,3. But now it shows 1,3,5.
Am I missing something?
Thank you!
Hello Adrian Lopez,
Adrian1504 said:When I connect my device it prints this notifications in the nrf Connect app:
- PHY updated (TX: LE 2M, RX: LE 2M)
- Connection parameters updated (interval: 11.25ms, latency: 0, timeout: 10000ms)
And in the terminal I am getting this messages:
- MTU exchange successful, new MTU: 244 bytes
- Data length updated. Length 251/27 bytes, time 2120/2120 us
So I think that the central is accepting the changes successfully and is setting the same parameters as in the link you provided me.
Thank you for clarifying - it is good to have it confirmed that you are using a 11.25 ms connection interval.
It seems that you have successfully changed your connection parameters, and so that should not be what is causing the issue with the throughput either. Could you detail how you are generating and queueing the data for sending again? It would be great to see the relevant code as well, if possible.
If the throughput is still an issue we will need to capture a sniffer trace of the communication between the devices. Are you familiar with the nRF Sniffer tool?
Best regards,
Karl
Hi Karl,
A small update, I changed some things in my code and was able to achieve now .9 Mbps, so I guess the way I am queueing the data and sending it is still not correct. I would be happy to be able to get it up to 1.2. Of course, I will leave some of my functions here:
static void simulate_dataX(void)
{
sensor_valueX++;
if (sensor_valueX == 9) {
sensor_valueX = 0;
}
}
static void simulate_data(void){
simulate_dataX();
simulate_dataY();
simulate_dataZ();
}
int my_lbs_send_sensor_notify(void)
{
if (!notify_sensor_enabled) {
return -EACCES;
}
return bt_gatt_notify(NULL, &accelerometer_svc.attrs[1],
&buffer,
sizeof(buffer));
}
static void pack_data(uint8_t x, uint8_t y, uint8_t z){
buffer[buffer_index].x = x;
buffer[buffer_index].y = y;
buffer[buffer_index].z = z;
buffer_index++;
if (buffer_index == BUFFER_SIZE){
int err = my_lbs_send_sensor_notify();
if (err) {
LOG_ERR("Notification failed: %d", err);
}
buffer_index = 0;
}
}
void send_data_thread(void)
{
while(1){
if(notify_sensor_enabled){ //Without this if I was only achieveing .02 Mbps
simulate_data();
pack_data(sensor_valueX,sensor_valueY,sensor_valueZ);
}
}
}
K_THREAD_DEFINE(send_data_thread_id, STACKSIZE, send_data_thread, NULL, NULL,
NULL, PRIORITY, 0, 0);
Here is the prj:
# nothing here CONFIG_LOG=y CONFIG_BT=y CONFIG_BT_PERIPHERAL=y CONFIG_BT_DEVICE_NAME="BLE Device" CONFIG_BT_DEVICE_APPEARANCE=0 #CONFIG_BT_BAS=y CONFIG_BT_GATT_CLIENT=y CONFIG_DEBUG_OPTIMIZATIONS=y CONFIG_DEBUG_THREAD_INFO=y CONFIG_FPU=y CONFIG_BT_PERIPHERAL_PREF_MIN_INT=30 CONFIG_BT_PERIPHERAL_PREF_MAX_INT=40 CONFIG_BT_PERIPHERAL_PREF_LATENCY=0 CONFIG_BT_PERIPHERAL_PREF_TIMEOUT=1000 CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS=y CONFIG_BT_USER_PHY_UPDATE=y CONFIG_BT_USER_DATA_LEN_UPDATE=y CONFIG_BT_CTLR_DATA_LENGTH_MAX=251 CONFIG_BT_BUF_ACL_RX_SIZE=251 CONFIG_BT_BUF_ACL_TX_SIZE=251 CONFIG_BT_L2CAP_TX_MTU=247 CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048 CONFIG_MAIN_STACK_SIZE=2048 CONFIG_BT_RX_STACK_SIZE=2048
If you need any other part of the code, let me know. Also, I am not familiar to this tool, but I will have a look at it! Thank you!
Best regards,
Adrian Lopez Vudoyra
Hello Adrian.
Thank you for clarifying - I am glad to hear that you are having progress on the throughput!
The next step in figuring out where the bottleneck in the communication is would be to gather a sniffer trace, so that we can verify that the application always have data ready to send, and whether there is anything hampering the data from being sent.
It could for instance here be that the application is not supplying the data fast enough due to other tasks taking time away from the data generation.
Have you had a look at my suggestion for sniffer in my previous comment?
Best regards,
Karl
Hello Karl,
Sorry for the late response. I have been trying to install it, but I ran into this problem:
"The term 'nrf_sniffer_ble.bat' is not recognized as
the name of a cmdlet, function, script file, or operable program."
I have already checked and I have python installed. Do you know what is the problem?
Hello again, Adrian
Thank you for your patience with this - I have been out of office due to the public easter holiday last week, but now I am back.
Please make sure that you have followed all the steps in the Installing the sniffer guide - especially the part on Installing the sniffer capture tool. Please do this, and let me know if the issue persists!
Best regards,
Karl