CC2640R2F: TI-RTOS application: I2C interrupt enabled on NVIC after startup

John Whitehouse

Part Number: CC2640R2F

Hello,

I've noticed that in a custom TI-RTOS application I'm working with, the I2C interrupt (exception 17; NVIC->ISER0 bit 1) is enabled after startup (i.e. at the beginning of main).

I've not been able to identify why this is. In stepping through the pre-main disassembly, it appears to be part of the XDC startup routine. There's nothing in my XDC configuration that explicitly identifies or enables the I2C peripheral, so I was wondering whether this is a default behaviour?

Any ideas why this might be happening? I am using the RTOS code in the CC2640R2F ROM ('RTOS_IN_ROM').

Many thanks,

John

over 4 years ago

0 IUsedToBeARealPerson (M-W) over 4 years ago

TI__Guru 58425 points

Hi John,

Could you potentially share or elaborate on what you do in your application? I'm not able to verify your findings, I can only see the RTC interrupt being enabled after the "startup" phase.

0 John Whitehouse over 4 years ago in reply to IUsedToBeARealPerson (M-W)

Intellectual 620 points

Hello,

Thanks for the prompt response.

I've recreated the same thing using the simple_peripheral example for the CC2640R2F Launchpad board: see below. I'm using SDK version 3.20. Looking at the NVIC->ISER0 register prior to executing main(), the I2C interrupt (bit 1, interrupt number 1) is enabled.

Any ideas?

Many thanks,

John

0 John Whitehouse over 4 years ago in reply to John Whitehouse

Intellectual 620 points

Hello,

Any further ideas / suggestions about what might be happening here?

Many thanks,

John

0 IUsedToBeARealPerson (M-W) over 4 years ago in reply to John Whitehouse

TI__Guru 58425 points

Hi John,

Sorry for this, I remember responding to this a few weeks ago but it seems my responds did not actually "stick".

Looking at your image, it is actually bit 5 (or 4 depending on how you want to count) being set, not bit 1. This corresponds to EVENT:CPUIRQSEL4 which is the RTC event, not the I2C event.

0 John Whitehouse over 4 years ago in reply to IUsedToBeARealPerson (M-W)

Intellectual 620 points

Hi M-W,

Ah, the classic reading of hexadecimal as binary! :-) Apologies for messing you around.

Is there a particular reason why the RTC event is enabled during startup? Is it in support of RTOS / Bluetooth activities?

Thanks,

John

0 IUsedToBeARealPerson (M-W) over 4 years ago in reply to John Whitehouse

TI__Guru 58425 points

Hi John,

No worries :)

The RTC is used as the TI-RTOS timer source which is the reason it is enabled during startup.

0 John Whitehouse over 4 years ago in reply to IUsedToBeARealPerson (M-W)

Intellectual 620 points

That's very helpful: thank you!

John

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CC2640R2F: TI-RTOS application: I2C interrupt enabled on NVIC after startup