CC2640R2F: why is HCI_EXT_SetSCACmd set invalid?

zhenhua He

Part Number: CC2640R2F

I need to use an internal RC oscillator, but the accuracy is not enough.

Refer to the method in the link below and use the function HCI_ EXT_ SetSCACmd(); When SCA is set to 0,40500 and tested for 60 seconds, the deviation is about 0.04s, which is equivalent to 666ppm.

software-dl.ti.com/.../custom-hardware.html -32-khz-crystal-less-mode

666ppm is obviously unacceptable.

Is SCA not set successfully?

How to determine whether the setting is successful?

Is there any other way to improve the accuracy of the internal RC oscillator?

test with simple_ peripheral_ oad_ offchip.

This problem involves a large number of orders that we have shipped, hope to help me solve it as soon as possible, thank you!

over 4 years ago

0 fredrikgk over 4 years ago

Expert 2160 points

Using the method you refer and described here: www.ti.com/lit/pdf/swra499 will ensure the timing in the BLE communication link is kept within 500 ppm. Following the step by step guide will automatically set SCA to 500 ppm. Note that SCA itself does not affect the actual timing, it is just a method for the BLE Stack to know its own accuracy and notify it to the other device in the communication link. SCA should be a number between 0 and 500 by the way, I am not sure what you mean by "0,40500".

The problem most likely lies with how you have set up the timing measurement.

0 zhenhua He over 4 years ago in reply to fredrikgk

Prodigy 90 points

40500 It's wrote it wrong.

I set the SCA to 0,40,500,There is no improvement in accuracy.

0 fredrikgk over 4 years ago in reply to zhenhua He

Expert 2160 points

As I wrote earlier, changing SCA value does not affect the actual accuracy. It is just a BLE Stack communication parameter.

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CC2640R2F: why is HCI_EXT_SetSCACmd set invalid?