CC2650 modified firmware for standby mode

Hi Maillard,

As your question pertains to the CC2650, I have moved your thread from the MSP Forum to the BLE Forum. Also could you provide more details on what you are trying to do?

Regards,
Akash Patel

Hi,

The power_saving by default is enabled. However, whether or not the battery lasts for 6 weeks depends on how long your connection interval is and slave latency, on top of that, the current consumption of your sensor.

Can you elaborate a little bit more about what functionality you want to have, how frequent you want the data to be updated and transmitted?

Hello,
I ha ve a project in an automobile industrie that is of coonected the CC2650 on Bluetoothat a data recoder.
The connection should be continu during 6eeks. That's I have planned a battery that will be able to provide the sensorTag.
What do i do manage it for that's works?

Regards,
Romain

Hi,

Again, could you please explain what data you are going to recorde(which indicate the sensor you are going to use)?
Or are you using all the sensors on sensortag?

What's the connection interval you want to use?

Hi,

I don't use all the sensors just  gyrometer and accelerometer.

The connection interval that i want to use is about more than 6 weeks.

Hi Romain,

What Christin was talking about was your question was totally depends on your application.
Simply, just for cc2640, it's possible to take over 6 weeks with coin cell. Even possible over 1~3 year.
I highly recommend to check current consumption step by step.
1) Only cc2640
2) + enable gyrometer
3) + enable accelerometer

Best Regards,
Ronie OH

Hi Ronie,

The goal for my project to connect the sensortag to a BLE recorder. This recorder is connected to the sensortag to realise acquisitions of acceleration, gyrometer, and magnetometer in vehicles of clients in basics conditions. The recorder start record each time the driver start his vehicule, and the duration of this instrumentation is about a month (without charging the sensortag that will have to stay awake all time). So we have combine the sensortag with an external batery that's sized supply this one for more than a month.

Actually, we have allready connected the sensortag to the data recorder and we can realise only short acquisition.

The problem now is to change the stand by dration to infinite (to maintaine the sensortag woked up during the month of record).

During the night, for example, when the client don't use his car, the sensortag will have to stay awake to be reconnected to our recorder when the driver will start his car in the mornig.

That's why we would like to change the sensortag's stand by duration by changing the soft/firmware but we don't know how.

Have you got a solution ?

Moreover, we would like to change the reconrding period in the soft too. Actualy the accelerometer's periode is near than a second and we would like to decrease it to acquire better datas.

Best Regards.

Romain

What are the connection parameters you are using on BLE recorder(are you using iPhone or Android phone)?

HW and OS will affect the connection parameter. Please take a look at below:

For iOS device, following is the spec decided by Apple

3.6 Connection Parameters The accessory isresponsible for the connection parameters used for the Low Energy connection. The accessory should request connection parameters appropriate for its use case by sending an L2CAP Connection Parameter Update Request at the appropriate time. See the Bluetooth 4.0 specification, Volume 3, Part A, Section 4.20 for details.

The connection parameter request may be rejected if it does not comply with all of these rules:

● Interval Max * (Slave Latency + 1) ≤ 2 seconds

● Interval Min ≥ 20 ms

● Interval Min + 20 ms ≤ Interval Max Slave Latency ≤ 4

● connSupervisionTimeout ≤ 6 seconds

● Interval Max * (Slave Latency + 1) * 3 < connSupervisionTimeout

If Bluetooth Low Energy HID is one of the connected services of an accessory, connection interval down to 11.25 ms may be accepted by the Apple product. The Apple product will not read or use the parameters in the Peripheral Preferred Connection Parameters characteristic. See the Bluetooth 4.0 specification, Volume 3, Part C, Section 12.5.

last for 6 weeks is not what I meant for connection interval.

Here is the definition of some connection parameters: 

Connection Interval : Determines how often the Central(BLE recorder) will ask for data from the Peripheral(sensortag). When the Peripheral requests an update, it supplies a maximum and a minimum wanted interval. The connection interval must be between 7.5 ms and 4 s

Slave latency: By setting a non-zero slave latency, the Peripheral(sensortag) can choose to not answer when the Central asks for data up to the slave latency number of times. However, if the Peripheral has data to send, it can choose to send data at any time. This enables a peripheral to stay sleeping for a longer time, if it doesn't have data to send, but still send data fast if needed. The text book example of such device is for example keyboard and mice, which want to be sleeping for as long as possible when there is no data to send, but still have low latency (and for the mouse: low connection interval) when needed

The shorter the connection interval is, the higher average current consumption it is. You can take our power calculator tool for estimating the battery life.

Did you disconnect the sensortag from BLE recorder when the car is not in use? Then sensortag will turn into advertising mode, which by default uses 100ms advertising interval, and it's not exactly power saving.

You can change advertising interval on sensortag easily if you have our BLE stack 2.1 and devpack debugger XDS110