What's the unit of advertising interval parameter?

[Xuhui Huang]

I am not a native English speaker, I am totally confused with this line of code where I have found in many samples

#define APP_ADV_INTERVAL 300 /**< The advertising interval (in units of 0.625 ms. This value corresponds to 25 ms). */

Could anyone help me on this? thank you

[Kevin K.]

The comment says the advertising interval is in units of 0.625ms. 0.625ms equals 0.000625 seconds. (ms stands for milliseconds). To get the advertising interval we just multiply APP_ADV_INTERVAL by the unit.

APP_ADV_INTERVAL * 0.000625 seconds = 300 * 0.000625 seconds = 0.1875 seconds

Hopefully that makes sense! I can try explaining it another way if you're still confused :)

[Xuhui Huang]

Thanks for your answer Kevin, I totally understand what you are talking about, but what make me really confused is the comment "This value corresponds to 25 ms", as you said, it should be 187.5 ms, do you think it is a typo?

[Kevin K.]

I think it is a typo. For 25 ms we would expect APP_ADV_INTERVAL to have a value of 40. In some of the other example applications (look at ble_app_gls) we see the correct value of 40 with an identical comment.

[Xuhui Huang]

Thank you very much Kevin, I just wanna make sure if it is a typo, thank you :)