Required Information regarding crystal frequency

Hi Siva,

The CPU will always run at 48 MHz, independent of clock source.

Cheers,
Fredrik

Hi Fredrik,

                   Ya. Does by changing this frequency functionality wise do we have any impact ??
Can you please give me brief description about this frequency usage.

Thanks in advance.

Thanks & Regards

Siva Krishna Kattinti

Hi Siva,

That line must reflect the actual CPU clock frequency. Since the CPU frequency can only be 48 MHz, you should not change that line of code.

Cheers,
Fredrik

Hi Fredrik,

                   What is the source of this frequency. Either it is taking as internal crystal or external crystal.

Thanks

Siva Krishna

If you are running on the 24MHz external crystal there is an internal frequency doubler enabled which provides a 48MHz clock to the MCU system.
The BIOS.cpuFreq.lo = 48000000; setting is used by all peripheral drivers so they are able to correctly set the bit rate of a transfer.

.:svend

Hi svend,
As per my understanding as we are giving 24 MHZ external crystal oscillator with that it is taking as doubler and changing it to 48MHZ. If we change crystal oscillator accordingly it will change. Correct me if I am wrong.


Thanks in advance for your response.

Thanks
Siva Krishna

Yes, but the device supports only using a 24MHz crystal.

.:svend

Ya Thanks.
Another doubt what I have is I am using Util_constructClock function from util.c to create one shot clock timer using TI RTOS.. Here If I am providing 43200 (12 Hours) of delay as expiring time the timer is expiring only after 250 seconds.

Thanks,
Siva Krishna

If you provide 43200 as argument to Util_constructClock which takes milliseconds as argument I would expect the clock to trigger after 43.2 seconds, not 12 hours.. Note that if you halt the device with the debugger the RTC used as the RTOS tick timer will also be paused until you resume execution again.

.:svend

Sorry for providing wrong data, Actually I am giving the value as 43200 seconds. Internally I am multiplying it with 1000. i.e., I am giving the value as 12 hours (12*60*60*1000 = 43200000) which will be equal to 12 hours. As already I checked for 8 hours (8*60*60*1000) which was giving accurate 8 hours duration and timer was expiring once it reaches 8 hours. But when I am trying for 12 hours (12*60*60*1000) timer was expiring after 250 seconds. Ya I am not halting the device. As you mentioned I am running the application.

Thanks,
Siva Krishna

Hi svend,
As per my understanding Clock.tickPeriod = 10; this variable we need to increase to 100 or 1000 like that. And what does mean by decrease the resolution? Correct me if I am wrong. I have another doubt, this clock.tick period will reflects the other tasks.

Thanks
Siva Krishna.

Hi svend,

                    I have changed the Clock.tickPeriod = 1000; And i tried to generate delay of 5 sec but it was not generating any delay. If I am doing 5 (5 * 1000) sec  then only it is getting 5 sec of delay. Can you please suggest me changing this clock.tickperiod in .cfg file is the only change what we need to do or any other file we have to change.

Thanks in advance.

Thanks
Siva Krishna

Hi svend,

I found my mistake. I was not assigning proper value to get delay. Know I was able to get the 5 seconds delay while putting tickperiod as 100us . Thank you so much for your support.

Thanks,

Siva Krishna.