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how to set the ACLK clock

Posted by ASHISH PATEL

on Apr 15 2012 02:45 AM

my problem is that i want to run ACLK and SMCLK both on controller MSP430F2616 but i am not able to run it

i give all setting for that

WDTCTL = WDTPW | WDTHOLD;

_BIS_SR(OSCOFF);
   BCSCTL1 |= 0x00;
   BCSCTL1 |= LFXT1S_0 + XTS ;
BCSCTL1 &= ~(XT2OFF);

// BCSCTL2 |= SELM_2 + SELS + DIVS_0;
BCSCTL3 |= XT2S_2 + XCAP_1 + LFXT1OF ;
do
{
IFG1 &= ~OFIFG;                           // Clear OSCFault flag
for (i = 0x0FF; i > 0; i--);             // Time for flag to set
}
while ((IFG1 & OFIFG));                   // OSCFault flag still set?

BCSCTL2 |= SELM_2 + SELS + DIVS_2 + DIVM_0 ;

using this i got the MCLK and SMCLK but using crystal 5Mhz i want to generate the ACLK
but its not coming properly its varying not coming constant

also i set the all PORT direction and all those thing plz help me

Posted by Chester Gillon

on Apr 15 2012 06:47 AM

Mastermind6315 points

ASHISH PATEL
also i set the all PORT direction and all those thing plz help me

To use the XT2 crystal oscillator the P8SEL.6 and P8SEL.7 bits need to be set (see the Port P8 (P8.6), Input/Output With Schmitt Trigger and Port P8 (P8.7), Input/Output With Schmitt Trigger diagrams in the MSP430F2616 datasheet SLAS541J)

i.e.the following code is required attempting to start the oscillator:

P8SEL |= BIT7 + BIT6;

Posted by ASHISH PATEL

on Apr 15 2012 08:22 AM

Prodigy230 points

Whatever ur ans is right but y controller is 60 Pins and also i got yhe XT2 output but i m not able to switch on the XT1 in any mode not in low frequency mode or high

frequency mode

i set the pin of ACLK both that P2.0 and also P5.6 using this P2SEL |= 0x01; P2DIR |= 0x01; P5SEL |= BIT6; P5DIR |= BIT6 then also i didn't get it .

Posted by Chester Gillon

on Apr 15 2012 13:34 PM

Mastermind6315 points

ASHISH PATEL
using this i got the MCLK and SMCLK but using crystal 5Mhz i want to generate the ACLK but its not coming properly its varying not coming constant

Can you clarify if a 5MHz crystal is connected to the XT1 and/or XT2 crystal oscillator?

Posted by old_cow_yellow

on Apr 15 2012 18:07 PM

Guru25795 points

(1) There is no 60-pin MSP430F2616. You must meant 64-pin.

(2) Your statement: _BIS_SR(OSCOFF); is wrong. You must delete that line.

(3) Your statement: BCSCTL1 |= 0x00; is useless. You should delete that line.

(4) The LFXT1S_0 part of your statement: BCSCTL1 |= LFXT1S_0 + XTS ; is inappropriate. You should edit that part out.

(5) Your statement: BCSCTL3 |= XT2S_2 + XCAP_1 + LFXT1OF ; is wrong. You must change it to: BCSCTL3 = XT2S_2 + LFXT1S_2;

(6) XT2 cannot be used to source ACLK and is enabled but not used in the above code. XT1 could and is selected as ACLK in the above code.