What is the meaning of number of _delay_cycles?

Yang ShunFan

Intellectual 570 points

Other Parts Discussed in Thread: TMS570LS1227

Dear all,

I am using TMS570LS1227 on CCS v6.1 (arm compiler 5.2.2).

As my know, the latest versiion of compiler(5.2.2) has supported _delay_cycles().

Could you explain what is the meaning of the number?

For example, if I use _delay_cycles(1000), what is its unit? 1000s? 1000 cpu clock?

Also, I had test the performance of _delay_cycles by RTI.

The _delay_cycles(1000) spend about 1.97 * 10^-5

The _delay_cycles(100000) spend about 1.94 * 10^-3

Thanks a lot

over 10 years ago

0 QJ Wang over 10 years ago

TI__Guru**** 197006 points

Hi ShunFan,

It might be CPU clock cycles. Could you please post this question to CCS forum for precise answer?

e2e.ti.com/.../81;pi317054=1

You can use _delay_cycle(x) for delays, but in that case you would be committing the CPU to a function that does not add much value to your application, and the code wastes power. The best way is to use a timer like you did using RTI. This is my opinion.

Regards,
QJ

0 Yang ShunFan over 10 years ago in reply to QJ Wang

Intellectual 570 points

Dear QJ,
Thanks your reply, I had posted this question to CCS forum.
Also, as your reply, its unit is CPU clock, thanks a lot.

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What is the meaning of number of _delay_cycles?