Compiler: #define CPU_RATE

Arash Tahghighi

Tool/software: TI C/C++ Compiler

Hi Forum

I am new with CCS, when I was going through the files on one the example "Example_F2802xLaunchPadDemo" I came across this definition

#define CPU_RATE 11.111L // for a 90MHz CPU clock speed (SYSCLKOUT)

one thing I notice is that CPU_RATE has not been used in any other files.

my question is:

1- where does this definition appear?

2- what is the usage of it? what is the cpu_rate in genera?

thanks in advanced

over 6 years ago

0 Keith Barkley over 6 years ago

Guru 43445 points

It is probably just a constant to calibrate some sort of delay for the Demo. Since it is floating point, it would not ge generally applicable to many other MCU's that prefer integers.

0 Devin Cottier over 6 years ago in reply to Keith Barkley

TI__Guru 60865 points

Hi Arash,

11.11ns would be the SYSCLK period if the device is operating at 90MHz. I'm not sure where this # define is used in the SW; I'll flag someone from the SW team to investigate.

Otherwise there isn't anything magic about this definition; it is just a constant used somewhere else in the SW.

0 MEGHANA MANAVAZHI over 6 years ago in reply to Devin Cottier

TI__Genius 10345 points

hi Arash,

This CPU_RATE MARCO is the equivalent SYSCLK period based on the frequency of operation. CPU_RATE is used to calculate the delay -> DELAY_US(x) macro.

#define DELAY_US(A)  DSP28x_usDelay(((((long double) A * 1000.0L) / \
                                    (long double)CPU_RATE) - 9.0L) / 5.0L)

The launchpad demo example uses these delays "DELAY_US(50000);" in the code which is calculated using this CPU_RATE macro.

Regards.

0 Arash Tahghighi over 6 years ago in reply to MEGHANA MANAVAZHI

Intellectual 630 points

Thanks Meghana,

yes My question is answered.

Regards

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Compiler: #define CPU_RATE