CCS/MSP430F247: Would like to know the external clock configuration

Hello Gary,

I believe that XIN can be connected to the external clock and XT2IN to VCC. If I disable XT2IN.

Am I correct?

Maneish

Hi Manesh

Please refer to the user's guide chapter 5.2.4 https://www.ti.com/lit/ug/slau144j/slau144j.pdf "XT2 may be used with external clock signals on the XT2IN pin when XT2Sx = 11 and XT2OFF = 0. When used with an external signal, the external frequency must meet the data sheet parameters for XT2. When the input frequency is below the specified lower limit, the XT2OF bit may be set to prevent the CPU from being clocked with XT2CLK"

Best regards

Gary

Hi Gary,

So does it mean that both XIN and XT2IN must be connected to the external Clock?

Thanks,

Maneish 

Hi Maneish

Just one of them. If your input a clock frequency more than 400K you can use the XT2IN. For more configure information please refer to the datasheet chapter "Crystal Oscillator XT2" https://www.ti.com/lit/ds/symlink/msp430f247.pdf

Best regards

Gary

In the document

MSP430x2xx Family
User's Guide

Under section

5.1 Basic Clock Module+ Introduction

LFXT1CLK: Low-frequency/high-frequency oscillator that can be used with low-frequency watch
crystals or external clock sources of 32768 Hz or with standard crystals, resonators, or external clock
sources in the 400-kHz to 16-MHz range.

So cant I understand that I can use XIN as external input with 16 Mhz.

Please confirm.

Please let me know if it's ok to feed 16 MHz to XIN as an external input clock.

based on the text

MSP430x2xx Family
User's Guide

Under section

5.1 Basic Clock Module+ Introduction

LFXT1CLK: Low-frequency/high-frequency oscillator that can be used with low-frequency watch
crystals or external clock sources of 32768 Hz or with standard crystals, resonators, or external clock
sources in the 400-kHz to 16-MHz range.