CCS/MSP430FR5972: MSP430FR5972

Hi Alexander

I notice that you have a lot of lines in your code similar to this one on line 7.

CSCTL1 !=  DCOFSEL_6;

Do you mean to check this for inequality, or do you mean to "or-equal" it like this?

CSCTL1 |=  DCOFSEL_6;

The statements in your code that use the != only check if the two arguments on either size of the != are not equal.  They do not actually set the values of any bits in the registers.  The |= will set the registers to their current value, "OR-ed" bitwise with the other value.

As well, can you explain what this code is intended to do?  The way I understand it, you're trying to set the DCO to 8 MHz, select the LFMODCLK as the source for the ACLK, and generate 500 interrupts per second using Timer2.  Is all of this completely correct?

Nate

thanks for the answer!

CSCTL1! = DCOFSEL_6;

I wrote on different C compilers, but more like "Kernighan + Richie C".
The constructions I wrote - I meant this:
to set the bit I want without changing the others:
P1DIR | = BIT4; P1OUT | = BIT4; // Set P1.4 to output direction

reset the bit I need without changing the others:
P1DIR & = ~ BIT0; P1OUT & = ~ BIT0; // Set P1.0 to input direction

"Bitwise OR" - the _result_ of the operation is 1 if one of the corresponding bits is 1, otherwise 0.

Set to 1 the zero bit of the P1OUT port (for example) can be as follows:

P1OUT = 0x01; // hexadecimal notation
or
P1OUT = 0b00000001; // binary record
or
P1OUT = 1; // decimal notation
But at the same time we "spoil" (overwrite) all the others to beat in P1OUT.
I need to install only one bit from the port (register) without changing the rest.

if we want to set in 1 only the zero bit(for example) and not touch the others?

In this case, you need to use "bitwise OR":

set zero bit to one
P1OUT = P1OUT | 0x01;
or by using compound assignment
P1OUT | = 0x01;
As a result, we changed only the zero bit of the port.

"Bitwise operation NOT" - changes the value of the bit to the opposite.
This operation together with the bitwise NOT can be used to reset a particular bit to zero.

reset zero bit
P1OUT & = 0xFE;
or
P1OUT & = ~ 0x01;

With such a record, we put a bit into the unit that we want to zero, then invert the resulting number, Now apply the resulting mask. As a result, we put 0 at only the first bit.

And the code of the program should be written so that you can read it later :)

I'm trying to set the DCO to 8 MHz, select the LFMODCLK as the source for the ACLK,

and generate 500 interrupts per second using Timer2.

Yes. correct.

I can not get to work Timer2 :-((

Code:

...

...
void _system_pre_init(void)
{
/* Insert your low-level initializations here */
 WDTCTL = WDTPW + WDTHOLD;  // Stop Watchdog timer

__disable_interrupt();  // Это специальная команда!  Это не прерывание.

 PM5CTL0 &= ~LOCKLPM5;           // Disable the GPIO power-on default high-impedance mode
                                 // to activate previously configured port settings
// Clock System Setup
 CSCTL0_H = CSKEY >> 8;                    // Unlock CS registers

 CSCTL1 = 0;
 CSCTL1 !=  DCOFSEL_6;                     // Set DCO setting for 8MHz --- установка частоты 8_Мгц

 CSCTL2 != SELA__LFMODCLK;        // 010b = LFMODCLK  (ACLK == MODOSC/128)
 CSCTL2 != SELS__DCOCLK;          // 011b = DCOCLK
 CSCTL2 != SELM__DCOCLK;          // 011b = DCOCLK

 CSCTL3 != DIVA__2;      // ACLK source divider. Divides the frequency of the ACLK clock source. 001b = /2
 CSCTL3 &= ~DIVS__1;      // SMCLK source divider. Divides the frequency of the SMCLK clock source. 000b = /1
 CSCTL3 &= ~DIVM__1;      // MCLK source divider. Divides the frequency of the MCLK clock source. 000b = /1

 CSCTL4 != HFXTOFF;      // 1b = HFXT is off if it is not used as a source for ACLK, MCLK, or SMCLK
 CSCTL4 &= ~VLOOFF;      // VLO off. This bit turns off the VLO. 0b = VLO is on
 CSCTL4 &= ~SMCLKOFF;    // SMCLK off. This bit turns off the SMCLK. 0b = SMCLK on
 CSCTL4 != LFXTOFF;      // 1b = LFXT is off if it is not used as a source for ACLK, MCLK, or SMCLK

 // CSCTL5 ???
 // CSCTL6 ???

 CSCTL0_H = 0;                             // Lock CS registers


//  Start init Timer2_A0,  ---------------------------------------------------------------------------

TA2CTL = 0;  //  all bits reset to =0
TA2CTL = TASSEL__SMCLK + ID__1 + MC__UP + TACLR;

/*
TASSEL__SMCLK;       // Timer_A clock source select 00b = TAxCLK  01b = ACLK 10b = SMCLK
TASSEL_2;            // Timer_A clock source select 00b = TAxCLK  01b = ACLK 10b = SMCLK
ID__1;               // Timer A input divider: 0 = /1 , 1 = /2 , 2 - /4 , 3 - /8
MC__UP;              // Timer A mode control: 1 - Up to CCR0
TAIFG;               // Timer_A interrupt flag 0b = No interrupt pending  1b = Interrupt pending
TAIE;                // Timer_A interrupt enable. This bit enables the TAIFG interrupt request. 0b = Interrupt disabled 1b = Interrupt enabled
TACLR;               // Timer_A clear.
*/

TA2CCTL0 = 0;   // all bits reset to =0
TA2CCTL0 &= ~CAP;              // Capture mode 0b = Compare mode 1b = Capture mode

//TA2EX0 &= ~TAIDEX_0;         // Timer_A Input divider expansion : /1
TA2EX0 = 0;

TA2CCR0 = 1000 - 1;   // may be 1000 per sec?  but really = 122(244) per sec ;-((

TA2CCTL0 = CCIE;
//  End init Timer2_A0  ---------------------------------------------------------------------

__bis_SR_register(GIE);

__enable_interrupt();

}

...

// Timer2_A0 interrupt service routine  -------------------------------------------------------
#pragma vector = TIMER2_A0_VECTOR
__interrupt void Timer2_A0_ISR (void)
{

     P4OUT ^= BIT2;                      // Toggle P4.2 using exclusive-OR (set-reset an LED)

     __no_operation();                       // for debugger
}
...

...

Work !. but................

TA2CCR0 = 1000 - 1;    may be 8000000 / 1000 = 8000 flash LED per sec? Yes-No?

If 8Mhz / 1000 = 8000 ? Really ? ;)

Really in my oscillograf i see 122Hz (meandr: 122Hz=0 and 122Hz=1)

i.e: 8000000 / 65573 = 122 ???

8-(

but really = 122(244) per sec ;-((

Hi Alexander

I see you still have some exclamation points "!", where you should have OR operators "|".   To fix that, change every != to |= in your code above.  

The other issue is the following lines

CSCTL3 &= ~DIVS__1;      // SMCLK source divider. Divides the frequency of the SMCLK clock source. 000b = /1

CSCTL3 &= ~DIVM__1;      // MCLK source divider. Divides the frequency of the MCLK clock source. 000b = /1

DIVS__1 and DIVM__1 are both equal to 0x0000.  So, when you run these lines, they do nothing, because they set

CSCTL3 = CSCTL3 & 0xFFFF;

which does not change CSCTL3 in the first place.  To fix this, set CSCTL = 0 before making other changes to it.

Finally, if you want to generate 500 interrupts per second, your pin will toggle every 2 milliseconds.  With an 8MHz Clock, that means you will want your counter to count up for 16000 cycles before triggering the interrupt.

I used the following code to get the following output on a logic analyzer.  I made as few changes to your original code as I could.

#include <msp430.h> 
int main(void)
{
    /* Insert your low-level initializations here */

     WDTCTL = WDTPW + WDTHOLD;  // Stop Watchdog timer
    __disable_interrupt();
     PM5CTL0 &= ~LOCKLPM5;           // Disable the GPIO power-on default high-impedance mode
                                     // to activate previously configured port settings
    // Clock System Setup
     CSCTL0_H = CSKEY >> 8;                    // Unlock CS register
     CSCTL1 = 0;
     CSCTL1 |=  DCOFSEL_6;                     // Set DCO setting for 8MHz


     CSCTL2 |= SELA__LFMODCLK;        // 010b = LFMODCLK  (ACLK == MODOSC/128)
     CSCTL2 |= SELS__DCOCLK;          // 011b = DCOCLK
     CSCTL2 |= SELM__DCOCLK;          // 011b = DCOCLK

     CSCTL3 = 0;             // Sets all source dividers to 1
     CSCTL3 |= DIVA__2;      // ACLK source divider. Divides the frequency of the ACLK clock source. 001b = /2

     CSCTL4 |= HFXTOFF;      // 1b = HFXT is off if it is not used as a source for ACLK, MCLK, or SMCLK
     CSCTL4 &= ~VLOOFF;      // VLO off. This bit turns off the VLO. 0b = VLO is on
     CSCTL4 &= ~SMCLKOFF;    // SMCLK off. This bit turns off the SMCLK. 0b = SMCLK on
     CSCTL4 |= LFXTOFF;      // 1b = LFXT is off if it is not used as a source for ACLK, MCLK, or SMCLK

     CSCTL0_H = 0;                             // Lock CS registers

    //  Start init Timer2_A0,  ---------------------------------------------------------------------------
    //TA2CTL = 0;  //  all bits reset to =0
    TA2CTL = TASSEL__SMCLK + ID__1 + MC__UP + TACLR;

    /*
    TASSEL__SMCLK;       // Timer_A clock source select 00b = TAxCLK  01b = ACLK 10b = SMCLK
    TASSEL_2;            // Timer_A clock source select 00b = TAxCLK  01b = ACLK 10b = SMCLK
    ID__1;               // Timer A input divider: 0 = /1 , 1 = /2 , 2 - /4 , 3 - /8
    MC__UP;              // Timer A mode control: 1 - Up to CCR0
    TAIFG;               // Timer_A interrupt flag 0b = No interrupt pending  1b = Interrupt pending
    TAIE;                // Timer_A interrupt enable. This bit enables the TAIFG interrupt request. 0b = Interrupt disabled 1b = Interrupt enabled
    TACLR;               // Timer_A clear.
    */


    TA2CCTL0 = 0;   // all bits reset to =0
    TA2CCTL0 &= ~CAP;              // Capture mode 0b = Compare mode 1b = Capture mode
    //TA2EX0 &= ~TAIDEX_0;         // Timer_A Input divider expansion : /1
    TA2EX0 = 0;
    TA2CCR0 = 16000 - 1;   // (8000000 cycles / 1 second) * (1 second / 500 interrupts) = 16000 cycles / interrupt
    TA2CCTL0 = CCIE;

    //Set P4 direction and output;
    P4DIR |= BIT2;
    P4OUT |= BIT2;


    //  End init Timer2_A0  ---------------------------------------------------------------------

    __bis_SR_register(GIE);
    __enable_interrupt();
    while(1){}
}

// Timer2_A0 interrupt service routine  -------------------------------------------------------

#pragma vector = TIMER2_A0_VECTOR
__interrupt void Timer2_A0_ISR (void)

{
     P4OUT ^= BIT2;                      // Toggle P4.2 using exclusive-OR (set-reset an LED)
     __no_operation();                       // for debugger
}