MSP430FR2355

Are you trying to measure the frequency of the MCU? Or some external frequency? What is the clock frequency of the MSP430FR2355?

Dear Keith

Thank you for your reply.

I want to measure external frequency using MCU.

What frequency crystal are you using for the MSP430FR2355? If you are *not* using a crystal, you can't measure an accurate frequency. What are your accuracy requirements?

Configure

ACLK = 32768Hz,
MCLK = DCO + XT1CLK REF = 8MHz,
SMCLK = MCLK/2 = 4MHz.

So, you have an 8 MHz crystal and want to measure a 4 MHz frequency?

Yes, It is external and It is changeable between 3-5 Mhz.

So, what are your accuracy requirements? You might need the 24 MHz SMCLK.

Thank you for your reply.

Yes, I will try with 24Mhz.
I think I should use XT1CLK( I am not sure). I couldn't find any example for this work.
How can I found frequency?

You should look at the

MSP4302235X_tb0_capture.c

and

MSP4302235X_tb0_22.c

To see how to capture the period and use an external source to trigger the clock.

Dear Keith

Thank you for your reply.

I tested 2 sample code but I couldn't understand correctly, I have some question

1- I am using MSP430Fr2355 Launchpad and I don't have access to Pin 2.7 for as a input, what should I do now? 

2- I should use TB0CLK for timer  and TB0TRG for trigger? could you please explain it what should I do.

3- Do I need to connect pins together for timer and trigger?? Because in this link connected 2 pins for timer and trigger together.

https://dev.ti.com/tirex/explore/node?node=AE1YXfIwoIIOovncrRHB2A__IOGqZri__LATEST

Best 

Dear Keith

Thank you for your reply.

I tested 2 sample code but I couldn't understand correctly, I have some question

1- I am using MSP430Fr2355 Launchpad and I don't have access to Pin 2.7 for as a input, what should I do now? 

2- I should use TB0CLK for timer  and TB0TRG for trigger? could you please explain it what should I do.

3- Do I need to connect pins together for timer and trigger?? Because in this link connected 2 pins for timer and trigger together.

https://dev.ti.com/tirex/explore/node?node=AE1YXfIwoIIOovncrRHB2A__IOGqZri__LATEST