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question about USB dongle as a BLE device
Bluetooth 4.0 standard as a provision：
“The timing of advertising events and connection events is determined using the sleep clock accuracy, with a driftless than or equal to ±500 ppm.”
But，the USB dongle does not use external crystal , and the accuracy of the internal RC is 2000ppm.
so，i want to know How TI does in the sample project “HostTestRelease ”
that project can use the USB dongle as master，and the CC2540EM as slave.
Anyone who does not know why
Did not anyone ever thought about this issue.
Looking for the positive response....
Even if it is not a real answer
No sleep timer is needed on the USB dongle as it doesn't enter sleep mode, being USB-powered. Please refer to the KeyFob design for battery powered applications.
--PS. If this answered your question, please hit Verify Answer
thank you for your reply
But I can not quite understand what you mean
on BLE stack ，Do not need a slow clock if not sleep？
The reason I raise that issue because i tried to change the 32k osc from external crystal to internal RC，but it can not connected with the iphone 4S
so i read the BT CORE 4.0 found that “The timing of advertising events and connection events is determined using the sleep clock accuracy, with a
drift less than or equal to ±500 ppm.”
Then i confused.
Finally where and what i can find the key KeyFob design for battery powerd application？
If you don't use power saving, i.e. the device never sleeps, there is no need for a dedicated slow and accurate sleep crystal.
However, if you want to use power saving, you can not use the internal RC oscillator instead of a dedicated crystal with the necessary accuracy.
I believe the text in the BT Core assumes that devices will sleep between advertising and connection events, but this is not necessary.
Reference designs can now be found on the wiki.
I will try it and report the results after finished
say thank you again
i have tried it and you are right
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