_delay_cycles

David Ramirez

Hi I have a question is the following

What is the difference between _delay_cycles (x) and __ delay_cycles (x) or is the same because it works well but when I put __ delay_cycles (x) I get a sign detectig SW delay loop

Thanks

over 12 years ago

0 Brian Boorman over 12 years ago

Guru 25210 points

I am not sure what you mean by "sign-detecting" loop. The prototype for __delay_cycles (with two _ prefixed) is:

void __delay_cycles(unsigned long cycles);

so the parameter should be interpreted as an unsigned number.

0 David Ramirez over 12 years ago in reply to Brian Boorman

Intellectual 870 points

void __delay_cycles(unsigned long cycles);

What it shows me is:

Detected SW delay loop using __delay_cycles .

Thanks

0 Dung Dang over 12 years ago in reply to David Ramirez

TI__Genius 17802 points

Hi David,

as Brian already pointed out, the proper prototype for the intrinsic function is void __delay_cycles(unsigned long cycles); (two leading underscores).

However, it sounded like your question was more related to the remark "Detected SW delay loop using __delay_cycles" generated by the compiler. If so, this remark is generated if you have ULP Advisor enabled in your compiler (CCS or IAR). This tool detects areas in your code that might have potential for power saving optimization. For example, a software delay loop (CPU active) can be substituted by a hardware timer countdown with CPU sleeping, if it makes sense for your application. If interested, you can find out more information on ULP Advisor here: http://processors.wiki.ti.com/index.php/ULP_Advisor?DCMP=MSP430&HQS=Other+OT+ulpadvisor

Regards,

Dung

0 David Ramirez over 12 years ago in reply to Dung Dang

Intellectual 870 points

Thanks for your answer

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_delay_cycles