CC2652R7: customize low power mode

Hi, 

Thank you for reaching out. 

You can consider setting the device in shutdown mode if you an external way to wake it up (e.g. button to be pushed or equivalent). If possible, this would save a lot of power.

Unless turned on by the application, the sensor controller will remain off. 

ravindu gunasekara said:

1. is there any available reference to create a custom low power mode?

There is no specific reference as we discourage such approach.

You can reference the Power driver to have an idea of what is done. 

ravindu gunasekara said:

2. Is there any reference on waking up time (max, avg) in these modes and in a custom mode? 

Timing and Switching mode can be found in the data sheet of the part - https://www.ti.com/lit/ds/symlink/cc2652r7.pdf (§7.14)

I hope this will help,

Best regards, 

Hi Clément,

I have checked with power.h and tried with HAl programming by accessing the required registers. Also, I have already tested the shutdown with external interrupt using power.h, but the Bluetooth is disconnecting. So, it's not suitable for my application.

1) The data sheet contains necessary registers to create a custom power mode, but TI discourages attempts on that.???   Why does TI discourage such approaches and what consequences can happen with custom modes?

2) So, I have no valid option but to use idle mode?

Pointing out anything will be much helpful and Any guidance or help in any manner will be much appreciated.  Thank you.

Hi,

ravindu gunasekara said:

1) The data sheet contains necessary registers to create a custom power mode, but TI discourages attempts on that.???   Why does TI discourage such approaches and what consequences can happen with custom modes?

TI recommends using the power driver as it is tested in the SDK regression tests. 

My experience is that developing a better (i.e. more adapted to a specific use case) power driver is possible but quickly escalate into a significant effort.

ravindu gunasekara said:

2) So, I have no valid option but to use idle mode?

I believe you should first review your requirement of keeping the radio on - I have never experienced such requirement before. 

Assuming you can leave the radio off in between the Bluetooth LE operations, then you can used the unmodified BLE5Stack with the unmodified power driver and the device will go to standby in between the Bluetooth LE operation. 

I hope this will help,

Best regards, 

Hi Clément,

Clément said:

I believe you should first review your requirement of keeping the radio on - I have never experienced such requirement before. 

The application needs to connect the app with 1 day continuously without disconnecting. that's why I need the rf core on, else the pairing process need to happen again and again. 

Clément said:

My experience is that developing a better (i.e. more adapted to a specific use case) power driver is possible but quickly escalate into a significant effort.

do you have any experience with any driver related update. it doesn't matter which, just need an example.  

Hi, 

ravindu gunasekara said:

The application needs to connect the app with 1 day continuously without disconnecting. that's why I need the rf core on, else the pairing process need to happen again and again. 

Fair that you want to maintain a connection for extended period of time - but the radio on the CC2652R7 will allow to maintain a connection even if the device goes to standby. The CC2652R7 actually integrates a RTC clock that will wake up the device (and its radio) in time for the connection events. 

Also, if the pairing process is a problem, you should consider using bonding. As in case the connection is unintentionally dropped, the pairing process will have to be repeated. 

ravindu gunasekara said:

do you have any experience with any driver related update. it doesn't matter which, just need an example.  

I believe you are asking for a power driver modification - I do not have such modification I can share as these changes are owned by the companies who implemented these. 

Best regards, 

Hi Clément,

Clément said:

but the radio on the CC2652R7 will allow to maintain a connection even if the device goes to standby

The datasheet says the RF is off in standby mode. 

Clément said:

if the pairing process is a problem, you should consider using bonding. As in case the connection is unintentionally dropped, the pairing process will have to be repeated. 

The low power mode is used more frequently. we intend to use 100ms power on time and 900ms sleep time per second continuously for a day. So, bonding might not be an option.

I have a question about the RF functionality in idle mode. So, according to the datasheet the RF core is on, and CPU is off. If the Bluetooth receive data from a service when device at the idle mode, what might happen. Can CPU wakeup from the Bluetooth event and go to idle mode again or stay on wake up or not receive the event.