Need to know how to implement a delay using the timers in TMS57020216LSUSB

Hi Gowdham,

It will be easier to use RTI to generate delay. The frequency of RTI is VCLK. The only thing you need is to program the RTI counter register.

Regards,

QJ

Hi Gowdham,

I agree with QJ that the RTI is a better option for just a periodic interrupt.   

RTI is the realtime interrupt module and it is usually used for operating system delays. 

NHET / HET are control timers - and typically they are used for input capture / output compare functions  where you need to drive IO pins.   NHET / HET each can drive a whole bunch of pins from one timer - which is one reason they're unique.

Still, if you really want to generate a simple periodic interrupt from NHET,  you could look at the NHET instruction "CNT".

The syntax of CNT (From the Technical Reference Manual) is :

CNT {
[brk={OFF | ON}]
[next={label | 9-bit unsigned integer}]
[reqnum={3-bit unsigned integer}]
[request={NOREQ | GENREQ | QUIET}]
[angle_count={OFF | ON}]
[reg={A | B | T | NONE}]
[comp ={EQ | GE}]
[irq={OFF | ON}]
[control={OFF | ON}]
max={25-bit unsigned integer}
[data={25-bit unsigned integer]
}

all the fields with [] are optional so your program could be as simple as:

START:   CNT {max = XYZ, irq=ON, data=0}

                 BR {event = NOCOND, cond_addr = START}

                                                         (note that I put the branch after CNT because a proper NHET program must be at least two instructions long...)

XYZ would be replaced by your desired period - say 3 seconds divided by the Loop resolution period of the NHET.    A typical value for the loop resolution period could be 1-2us so even with the 25 bit value for max you should be able to reach 3 seconds...

The field irq=ON means the CNT instruction generates an interrupt when it rolls over from max back to zero.    Internally, the NHET has multiple interrupt channels that it maps to two different interrupt lines going back to the CPU.    The channel number depends on the address of the CNT instruction in the NHET code; and there are control registers that need to be setup in the NHET, VIM, and CPU to enable the interrupt.  

That's just a teaser for NHET in case you want to experiment.  Of course this program is too simple really for NHET and that's why RTI is a good choice.

But if you every want to do something more interesting, like coordinate the delay with some IO activity - say interrupt the CPU whenever either a pin toggles or 3s which ever comes first, then this is where you might want to look at NHET.

Hi Gowdham,

I didn't read this appnote before. The sample code in the appnote (SPNA123.PDF) uses RTI INT for toggling GIO pins. Do you only use it for SW delay in your bootloader, right?

For RTI INT enable function, 2 statement is enough. They are used to enable/disbale the INT for the module (RTI, DCAN, ..) and set the IRQ/FIQ priority for each INT. please refer to databook to understand the INT request assignment.

    /* set IRQ/FIQ priorities */
    vimREG->FIRQPR0 |=  (SYS_FIQ <<  1U)        
                    | (SYS_IRQ <<  2U)          /*2, RTI compare INT0*/
                    | (SYS_IRQ <<  3U)          /*3, RTI compare INT1*/        
                    | (SYS_IRQ <<  4U)          /*4, RTI compare INT2*/
                    | (SYS_IRQ <<  5U)          /*5, RTI compare INT3*/
                    | (SYS_IRQ <<  6U)          /*6, RTI overflow INT0*/
                    | (SYS_IRQ <<  7U)          /*7, RTI overflow INT1*/
                    | (SYS_IRQ <<  8U)          /*8, RTI Timebase*/

    /* enable interrupts */
    vimREG->REQMASKSET0 |= (1U << 2)             /*1: enable*/
                        | (0U << 3)              /*0: disable*/ 
                        | (0U << 3)
                        | (0U << 4)
                        | (0U << 5)
                        | (0U << 6)
                        | (0U << 7)
                        | (0U << 8); 

For VIM_RAM_INT, you can use this way:

typedef volatile struct vimRam
{
    t_isrFuncPTR ISR[VIM_CHANNELS];
} vimRAM_t;

#define vimRAM ((vimRAM_t *)0xFFF82000U)    /*VIM RAM*/

void VIM_RAM_Init(void)
{
  int i;
  for (i=0;i < VIM_CHANNELS;i++)
 {
  vimRAM->ISR[i] = &phantomInterrupt;
 }
  vimRAM->ISR[2+1]   = &rtiCompare0Interrupt;      //ISR in your code
  vimRAM->ISR[21+1]  = &sciLowLevelInterrupt1;
  vimRAM->ISR[0+1]   = &esmHighLevelInterrupt;
  vimRAM->ISR[22+1]  = &can1HighLevelInterrupt;
  vimRAM->ISR[29+1]  = &can2HighLevelInterrupt;
}

Regards,

QJ

HI Gowdham,

You assigned the ISR address to the vimRAM table, so you need to define the ISR in your project too. Otherwsie, you will get errors.

Regards,

QJ