there is interference in pins used as output when I use BLE ???

RE: there is interference in pins used as output when I use BLE ???

CesarBV — Fri, 29 Aug 2014 17:39:43 GMT

and this is my code for timer to generate pwm

//Define para TIMER

#define PWM_OUTPUT_PIN_NUMBER (25)

#define MAX_SAMPLE_LEVELS (256UL) /< Maximum number of sample levels. */ #define TIMER_PRESCALERS 6U /< Prescaler setting for timer. */ #define GPIOTE_CHANNEL_NUMBER_2 1

///// TIMER /////

static __INLINE uint32_t next_sample_get(void) { static uint32_t sample_value = 8;

// Read button input.
sample_value = ((/*nrf_gpio_port_read(NRF_GPIO_PORT_SELECT_PORT0)*/0x000000BF) & 0x000000FFUL); // valor del ciclo de trabajo

// This is to avoid having two CC events happen at the same time,
// CC1 will always create an event on 0 so CC0 and CC2 should not.
if (sample_value == 0) 
{
    sample_value = 8;
}

return (uint32_t)sample_value;

}

/** @brief Function for handling timer 2 peripheral interrupts. */ void TIMER2_IRQHandler(void) { static bool cc0_turn = false; /**< Keeps track of which CC register to be used. */

if ((NRF_TIMER2->EVENTS_COMPARE[1] != 0) && 
   ((NRF_TIMER2->INTENSET & TIMER_INTENSET_COMPARE1_Msk) != 0))
{
    // Sets the next CC1 value
    NRF_TIMER2->EVENTS_COMPARE[1] = 0;
    NRF_TIMER2->CC[1]             = (NRF_TIMER2->CC[1] + MAX_SAMPLE_LEVELS);

    // Every other interrupt CC0 and CC2 will be set to their next values.
    uint32_t next_sample = next_sample_get();

    if (cc0_turn)
    {
        NRF_TIMER2->CC[0] = NRF_TIMER2->CC[1] + next_sample;
    }
    else
    {
        NRF_TIMER2->CC[2] = NRF_TIMER2->CC[1] + next_sample;
    }
    // Next turn the other CC will get its value.
    cc0_turn = !cc0_turn;
}

}

/** @brief Function for initializing the Timer 2 peripheral. */ static void timer2_init(void) { // Start 16 MHz crystal oscillator . NRF_CLOCK->EVENTS_HFCLKSTARTED = 0; NRF_CLOCK->TASKS_HFCLKSTART = 1;

// Wait for the external oscillator to start up.
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0) 
{
    //Do nothing.
}

NRF_TIMER2->MODE        = TIMER_MODE_MODE_Timer;
NRF_TIMER2->BITMODE     = TIMER_BITMODE_BITMODE_16Bit << TIMER_BITMODE_BITMODE_Pos;
NRF_TIMER2->PRESCALER   = TIMER_PRESCALERS;

// Clears the timer, sets it to 0.
NRF_TIMER2->TASKS_CLEAR = 1;

// Load the initial values to TIMER2 CC registers.
NRF_TIMER2->CC[0] = MAX_SAMPLE_LEVELS + next_sample_get();
NRF_TIMER2->CC[1] = MAX_SAMPLE_LEVELS;

// CC2 will be set on the first CC1 interrupt.
NRF_TIMER2->CC[2] = 0;

// Interrupt setup.
NRF_TIMER2->INTENSET = (TIMER_INTENSET_COMPARE1_Enabled << TIMER_INTENSET_COMPARE1_Pos);

} ///// TIMER /////

RE: there is interference in pins used as output when I use BLE ???

CesarBV — Fri, 29 Aug 2014 17:37:37 GMT

I've decided to use a PWM generated with timer interrupts to generate the signal I need for LCD. To do this I have modified the example "pwm_example" (eliminating the part of reading buttons) and added to my code above. But now doesn't work nothing, I have no signal in no any pin. So my question is the next, is there a problem between the configuration of the timers??? because I need one timer for pwm and BLE needs one timer too...

This is my code for the timers configuration

For timer used by BLE

#define APP_TIMER_PRESCALER 0 /< Value of the RTC1 PRESCALER register. */ #define APP_TIMER_MAX_TIMERS 2 /< Maximum number of simultaneously created timers. */ #define APP_TIMER_OP_QUEUE_SIZE 4 /**< Size of timer operation queues. */

static void timers_init(void) { // Initialize timer module, making it use the scheduler APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_MAX_TIMERS, APP_TIMER_OP_QUEUE_SIZE, true);

}

RE: there is interference in pins used as output when I use BLE ???

Nikita — Sun, 24 Aug 2014 06:22:43 GMT

You can know when softdevice will take over cpu time with radio notification event devzone.nordicsemi.com/.../ and don't update LCD if you don't have enough time to perform LCD update.

RE: there is interference in pins used as output when I use BLE ???

CesarBV — Sat, 23 Aug 2014 22:39:24 GMT

Thanks, I'll check it out and I'll comment here the results.

RE: there is interference in pins used as output when I use BLE ???

CesarBV — Sat, 23 Aug 2014 22:38:39 GMT

I need a signal to control a LCD display, that is the reason because I need to eliminate the latency. When latency is present, the icons in the display are flashing.

RE: there is interference in pins used as output when I use BLE ???

CesarBV — Sat, 23 Aug 2014 21:22:48 GMT

so, that means that this latency is not possible to eliminate????

RE: there is interference in pins used as output when I use BLE ???

Janek Mann — Sat, 23 Aug 2014 10:34:27 GMT

You can likely achieve the effect you are aiming for (a stable clock output on a pin) using the timer peripheral, you can look at the pwm library for inspiration: github.com/.../nrf51-pwm-library

RE: there is interference in pins used as output when I use BLE ???

Nikita — Sat, 23 Aug 2014 05:04:50 GMT

Read more about how softdevice works in S110_SoftDevice_Specification_v1.3A.pdf.

It's because softdevice managing your advertising and every advertising event CPU goes from the main to the softdevice to send advertising packets so you some latency in the main.