MSP430FR5994: LFXT oscillator crystal frequency support

Lina Lian

Part Number: MSP430FR5994

Hi All,

In MSP430FR5994 spec, it seems that if use external LFXT, external oscillator crystal frequency typical value is 32768Hz. If use 32kHz external crystal while OALFXT and Integrated load capacitance of LFXIN and LFXOUT is in allowed range, is there any potential risk? Or would you please help share allowed frequency range for external LFXT? Thanks a lot.

BR,

Lina

over 7 years ago

0 Ryan Brown1 over 7 years ago

TI__Guru**** 211777 points

Hi Lina,

A LFXT of 32768 is highly recommended but square wave input frequencies from 10.5 to 50 kHz are allowed and frequencies above the maximum oscillator fault frequency of 3.5 kHz will not set the fault flag. Therefore a 32 kHz watch crystal is allowable, once more not recommended since it is by no means a power of 2.

Regards,
Ryan

0 Lina Lian over 7 years ago in reply to Ryan Brown1

TI__Intellectual 1570 points

Ryan,
Thanks a lot for your kindly reply and help. One more question, what's the meaning of "a power of 2", does it mean if LFXT is out of allowed range, MSP430 need to take more extra power to driver it? Thanks.

BR,
Lina

0 Ryan Brown1 over 7 years ago in reply to Lina Lian

TI__Guru**** 211777 points

2^15 = 32768, this does not mean that other LFXTs are out of range or that the MSP430 requires extra power to drive it.

Regards,
Ryan

0 Lina Lian over 7 years ago in reply to Ryan Brown1

TI__Intellectual 1570 points

Ryan,

Got it. Thanks a lot.

BR,

Lina

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

MSP430FR5994: LFXT oscillator crystal frequency support