MSP430FR2355: 32-bit counter / timer without external pin interconnection.

Carlos Takahashi

Part Number: MSP430FR2355

Hello support team.

I am using the MSP430FR2355 VQFN-32 and I want to confirm if it is possible to connect Timer0_B3 and Timer1_B3 in cascade without the need to connect external pins.
Looking at pages 73 and 74 of the datasheet, it looks like Timer0_B3's CCR2 can take the Timer1_B3_INCLK output.
I intend to configure Timer0 to be the LSB, receiving SMCLK of 25 MHz and Timer1 receiving the overflow of Timer0 and being the MSL of a 32 bit counter.
Could you confirm me if this is possible without connecting external pins and don't want to take advantage, could you tell me the values of the Timer0_B and Timer1_B registers that I should configure?

Best Regards.

over 3 years ago

0 Eddie LaCost over 3 years ago

TI__Mastermind 38620 points

Hi Carlos,

I believe you need to have the external connection. See the app note below and code example.

https://www.ti.com/lit/an/slaa726/slaa726.pdf

0 Carlos Takahashi over 3 years ago in reply to Eddie LaCost

Intellectual 430 points

Hi Eddie.
Thanks for the answer.
I understood that it will be necessary to make an external connection.
Can I use TB2 as LSB and TB1 as MSB?
In this case, I intend to use SMCLK as TB2 clock, I will configure TB2 for continuous mode and CCR1 to generate pulses in the overflow on the TB2.1 pin.
The TB2.1 pin I will connect it to the TB1CLK clock input, I will also configure TB1 for continuous mode.
I consulted the datasheet, I saw that SMCLK can operate up to 24 MHz, I also looked at the errata file and found no frequency restrictions. So in theory, I think I can count for a period of (2 ^ 32) / (24 * 10 ^ 6) = 178.957 seconds.
I don't have the LaunchPad for MSP430FR2355 to test, could you confirm that this is right?

Best Regards.

0 Carlos Takahashi over 3 years ago in reply to Carlos Takahashi

Intellectual 430 points

Hi Eddie.
Could you tell me if what I said in the previous post is right?

Best Regards.

+1 Eddie LaCost over 3 years ago in reply to Carlos Takahashi

TI__Mastermind 38620 points

Hi Carlos,

Sorry for the delay.

Yes, you could use TB2 as LSB and TB1 as MSB. Your theory looks correct here with 24MHz SMCLK.

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MSP430FR2355: 32-bit counter / timer without external pin interconnection.