ESR Value for MSP430F5418A

Hi,

did you set the correct drive strength in UCSCTL6 according to the crystal's frequency?

Dennis

Dennis,

Thank you for your response.  I am looking at the UCSCLT6 register and it appears to only have references for crystals operating in the megahertz range.  This projects uses a 32kHz oscillator.  Am I not understanding the register values correctly?

--Timothy

Hello,

You may also find the following application note of some use.

www.ti.com/lit/slaa322
MSP430 32-kHz Crystal Oscillators

Regards,
JH

Jace,

I found this document previously. It does not cover the MSP430F518 series. Is their a second document which has this information?

--Timothy

Timothy,

This document applies to all MSP430 Families and is a general tool for getting 32-kHz oscillators to work consistently with our devices.

regards,
JH

You are right, the settings in UCSCTL6 are for HF crystals, not for the 32k768 one. You did not say which one you are talking about, so I guessed and was wrong :) Happens... Do you have additional load capacitance attached to your crystal?

Dennis,

I do not have any external capacitors attached to the oscillator.  However, I set the internal capacitance to the default value, 12pf.  I tried each of the values available, and none had any effect.  I have also adjust power to the xt1 pin and switched the crystal oscillator. 

--Timothy

Timothy,

What is the effective load capacitance value for your xtal? Can you link to its datasheet?

regards,
JH

JH, Here is the datasheet.

www.mouser.com/.../1705479-465430.pdf

Timothy,

What is your xtal full part number? By having this, we can determine the xtal's exact specs.

Regards,
JH

JH,

The following is the exact part number:

EPSON #MC-306 32.7680K-E3

Thank you,

Timothy

Timothy,

Your crystal has an Effective Load Capacitance of 6pF. The integrated capacitance is Effective Load capacitance, not straight Capacitance. This means you will need to set the XCAPx register =1 ( 6pF Effective Load Capacitance). Please also keep in mind for this xtal, set XT1DRIVEx =1 as well.

Regards,
JH

JH,

Thank you for the correct values.  In order to see if the board can function using the settings you provided, I attempted to make a simple pin high/pin low program.  For some reason, I seem to be unable to modify the registers on the micro-controller.  My sample code is given below.  Is my methodology for setting and clearing register bits incompatible with the msp430 series?  Thank you.

--Timothy Struble-Larsen

#include <msp430f5418.h> // header file that depends upon your variant

#define BV(bit) (1 << bit)

#define setBit(word,bit) (word |= BV(bit))

#define clearBit(word,bit) (word &=~BV(bit))

#define toggleBit(word,bit) (word ^=BV(bit))

/*

* main.c

*/

int main(void) {

setBit(UCSCTL6,6);

clearBit(UCSCTL6,7);

//UCSCTL6=UCSCTL6 & ~(0x40);

//UCSCTL6=UCSCTL6 & ~(0x80);

　

clearBit(UCSCTL6,3);

setBit(UCSCTL6,2);

//UCSCTL6=UCSCTL6 |0x04;

//UCSCTL6=UCSCTL6 |0x40;

WDTCTL = WDTPW | WDTHOLD;// Stop watchdog timer

P1DIR = 0X41; //Declare PIN0 AND PIN1 OF PORT 1 AS OUTPUT

P1OUT = 0X01; //MAKE PIN0 HIGH AND PIN1 LOW INITIALLY

unsigned int i; //Delay variable

while(1)

{

toggleBit(P1OUT,0);

//P1OUT ^=0X41; //Toggle the respective by using bit-xor operator

　

for(i=0;i<100;i++){ //Necessary delay, change it to see the effect on toggling

}

}

return 0;

}

alright, I figured out that I need to use "BIT4" instead of "1<<4." Now I can write to the registers. However, I still cannot get a sinewave out of any of the oscillators. Here is my new code:

#include <msp430f5418.h> // header file that depends upon your variant

#define BV(bit) (1 << bit)
#define setBit(word,bit) (word |= bit)
#define clearBit(word,bit) (word &= ~bit)
#define toggleBit(word,bit) (word ^= bit)
/*
* main.c
*/
int main(void) {

setBit(UCSCTL6,BIT6);
clearBit(UCSCTL6,BIT7);
//UCSCTL6=UCSCTL6 & ~(0x40);
//UCSCTL6=UCSCTL6 & ~(0x80);


clearBit(UCSCTL6,BIT3);
setBit(UCSCTL6,BIT2);

//UCSCTL6=UCSCTL6 |0x04;
//UCSCTL6=UCSCTL6 |0x40;
WDTCTL = WDTPW | WDTHOLD;// Stop watchdog timer

P1DIR = 0X41; //Declare PIN0 AND PIN1 OF PORT 1 AS OUTPUT

P1OUT = 0X01; //MAKE PIN0 HIGH AND PIN1 LOW INITIALLY

unsigned int i; //Delay variable
while(1)
{
toggleBit(P1OUT,BIT0);

}

return 0;

I figured out that I need to use "BIT4" instead of "1<<4."

BIT4 means 0001 0000 in binary

1<<4 means shifting 0000 0001 left by 4 which results in 0001 0000

That means, both is the same.

Dennis