TMS320F28P650DK: How do I set the timer period to 100ns?

Part Number: TMS320F28P650DK

Tool/software:

Hello everyone,

how can I change the timer period to get a timer interrupt every 100ns?

Unfortunately I can only set a minimum of 2us.

My current code:

//#############################################################################
//
// FILE:   timer_ex1_cputimers.c

//
// Included Files
//
#include "driverlib.h"
#include "device.h"

//
// Function Prototypes
//
__interrupt void cpuTimer0ISR(void);
void initCPUTimers(void);
void configCPUTimer(uint32_t, float, float);

//
// Main
//
void main(void)
{
    //
    // Initializes device clock and peripherals
    //
    Device_init();

    Device_initGPIO();

    //
    // Initializes PIE and clears PIE registers. Disables CPU interrupts.
    //
    Interrupt_initModule();

    //
    // Initializes the PIE vector table with pointers to the shell Interrupt
    // Service Routines (ISR).
    //
    Interrupt_initVectorTable();

    //
    // ISRs for each CPU Timer interrupt
    //
    Interrupt_register(INT_TIMER0, &cpuTimer0ISR);

    //
    // Initializes the Device Peripheral. For this example, only initialize the
    // Cpu Timers.
    //
    initCPUTimers();

    //
    // Configure CPU-Timer 0 to interrupt every ... seconds:
    // 1 Period respectively (in uSeconds)
    //
    configCPUTimer(CPUTIMER0_BASE, DEVICE_SYSCLK_FREQ, 0.2);

    //
    // To ensure precise timing, use write-only instructions to write to the
    // entire register. Therefore, if any of the configuration bits are changed
    // in configCPUTimer and initCPUTimers, the below settings must also
    // be updated.
    //
    CPUTimer_enableInterrupt(CPUTIMER0_BASE);

    //
    // Enables CPU int1 which are connected to CPU-Timer 0, respectively.
    // Enable TINT0 in the PIE: Group 1 interrupt 7
    //
    Interrupt_enable(INT_TIMER0);

    //
    // Starts CPU-Timer 0.
    //
    CPUTimer_startTimer(CPUTIMER0_BASE);

    //
    // Enable Global Interrupt (INTM) and realtime interrupt (DBGM)
    //
    EINT;
    ERTM;

    GPIO_writePin(0, 1);
    GPIO_setPinConfig(GPIO_0_GPIO0);
    GPIO_setDirectionMode(0, GPIO_DIR_MODE_OUT);

    //
    // IDLE loop. Just sit and loop forever (optional)
    //
    while (1)
    {
    }
}

//
// initCPUTimers - This function initializes all three CPU timers
// to a known state.
//
void initCPUTimers(void)
{
    //
    // Initialize timer period to maximum
    //
    CPUTimer_setPeriod(CPUTIMER0_BASE, 0xFFFFFFFF);

    //
    // Initialize pre-scale counter to divide by 1 (SYSCLKOUT)
    //
    CPUTimer_setPreScaler(CPUTIMER0_BASE, 0);

    //
    // Make sure timer is stopped
    //
    CPUTimer_stopTimer(CPUTIMER0_BASE);

    //
    // Reload all counter register with period value
    //
    CPUTimer_reloadTimerCounter(CPUTIMER0_BASE);


}

//
// configCPUTimer - This function initializes the selected timer to the
// period specified by the "freq" and "period" parameters. The "freq" is
// entered as Hz and the period in uSeconds. The timer is held in the stopped
// state after configuration.
//
void configCPUTimer(uint32_t cpuTimer, float freq, float period)
{
    uint32_t temp;

    //
    // Initialize timer period:
    //
    temp = (uint32_t) ((freq / 1000000) * period);
    CPUTimer_setPeriod(cpuTimer, temp - 1);

    //
    // Set pre-scale counter to divide by 1 (SYSCLKOUT):
    //
    CPUTimer_setPreScaler(cpuTimer, 0);

    //
    // Initializes timer control register. The timer is stopped, reloaded,
    // free run disabled, and interrupt enabled.
    // Additionally, the free and soft bits are set
    //
    CPUTimer_stopTimer(cpuTimer);
    CPUTimer_reloadTimerCounter(cpuTimer);
    CPUTimer_setEmulationMode(cpuTimer,
                              CPUTIMER_EMULATIONMODE_STOPAFTERNEXTDECREMENT);
    CPUTimer_enableInterrupt(cpuTimer);

}

//
// cpuTimer0ISR
//
__interrupt void cpuTimer0ISR(void)
{
    GPIO_writePin(0, 1);
    GPIO_writePin(0, 0);

    //
    // Acknowledge this interrupt to receive more interrupts from group 1
    //
    Interrupt_clearACKGroup(INTERRUPT_ACK_GROUP1);
}



//
// End of File
//

Kind regards