How to printf to BLE Central (iPhone)

RE: How to printf to BLE Central (iPhone)

Stefan_B — Mon, 21 Feb 2022 20:09:05 GMT

Yes, thank you!
I overlooked that the sprintf function is present. Documentation can also be found on the Segger website: studio.segger.com/index.htm

RE: How to printf to BLE Central (iPhone)

Karl Ylvisaker — Mon, 21 Feb 2022 12:45:39 GMT

Hello,

[quote user="Stefan_B"]thanks for your response![/quote]

No problem at all, I am happy to help!

[quote user="Stefan_B"]Is there a sprintf?[/quote]

Yes, this is the function you should use for the purpose you describe.
Generate the string using sprintf and transfer it using the NUS service.

[quote user="Stefan_B"]Where can I find documentation on the supported standard string functions?[/quote]

You read about and see all the standard IO functions in the stdio.h file included in the Segger Embedded Studio files.

Best regards,
Karl

RE: How to printf to BLE Central (iPhone)

Stefan_B — Mon, 21 Feb 2022 10:50:47 GMT

Hi Karl,

thanks for your response!

Yes, the nus service does not seem to be a problem. I have already tested that (with App_uart).

But I would have to recode the printf function. How else should I embed numerical values, e.g. "speed(kmh)=%d" or "battery voltage=%d V" etc.?

Where can I find documentation on the supported standard string functions? Is there a sprintf?

Somehow I have to convert numbers to strings. (That's what I mean by "having to reinvent the wheel". That would be sad).

RE: How to printf to BLE Central (iPhone)

Karl Ylvisaker — Mon, 21 Feb 2022 09:20:13 GMT

Hello,

[quote user=""]So how would I use printf to embed the numbers into strings and send them using the nus service? (without having to reinvent the wheel).[/quote]

Could it be an option to just use the BLE NUS service directly, with no use of the printf function?
The printf function are retargetted to the UART using the retarget library, but there is no implementation for it to retarget to the BLE NUS service.

Are you already familiar with the BLE NUS service and how to use it?

Best regards,
Karl