Change 32kHz MSP430x2xx external timer

Aitorhh

Hi,

We are using the MSP430x1xx series with an external 32.768 kHz crystal, but for our application the times given by this crystal are not enough. We need a timer that triggers every 16us.

We have seen that with the MSP430x2xx series is possible to change the clock source of 32.768 kHz with another in the 400kHz to 16 MHz range using the LFXT1CLK with the HF mode enabled, is it correct? Are there some test with different clock sources like http://www.ti.com/lit/pdf/slaa225 for the 32.768 kHz?

Thanks in advance

over 15 years ago

0 old_cow_yellow over 15 years ago

Guru 58965 points

Not sure which device you are using. But the data-sheet of that device probably specified the frequency range in LF mode as well as in HF mode. You also have the option of feeding you device with an externally generated clock (instead of connecting to a crystal to generate the clock).

0 Joerg Quinten over 15 years ago in reply to old_cow_yellow

Guru 17650 points

Hi,

if you need accurate timing you should think about using an oszillator instead of a crystal; i.e. something like http://www.sitime.com/products/high-performance-programmable-oscillators.php.

I.e. this one http://www.sitime.com/products/sit8102.php gives you a frequency tolerance of +/-10ppm (at 0° to 70°C).

Rgds
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Change 32kHz MSP430x2xx external timer