ESP32 Forum

Hello,

will the hardware counter start immediately when it is correct configured? Or is any trigger/start required?

In my tests the count register is always 0x0000, (not counting). I cant get it to count.
Goal of my tests was to count level changes on one gpio-pin (22).
I am not using the IDF driver.
The counter 0 is not paused. And not cleared.

I played with the counter-settings and verified them by a memory dump. My app parses the settings to the hardware.
define myS0 esp32_S0 CNT_UNIT=0&CH0_POS_MODE=inc_counter&CH0_NEG_MODE=inc_counter&CH0_HCTRL_MODE=no_modification&CH0_LCTRL_MODE=no_modification&THR_L_LIM_EN=Disabled&THR_H_LIM_EN=Disabled&THR_ZERO_EN=Disabled&THR_THRES0_EN=Disabled&THR_THRES1_EN=Disabled&FILTER_EN=Disabled


I searched for the problem. What i did before setting up counter 0 itself:

// enable the counter
SET_PERI_REG_MASK(DPORT_PERIP_CLK_EN_REG, DPORT_PCNT_CLK_EN);
CLEAR_PERI_REG_MASK(DPORT_PERIP_RST_EN_REG, DPORT_PCNT_RST);

// config the gpio + gpio_matrix_in
pcnt_unit_t unit = 0;
pcnt_channel_t channel = 0;
int pulse_io = 22;
int ctrl_io = 21;

int input_sig_index = (channel == 0 ? PCNT_SIG_CH0_IN0_IDX + 4 * unit : PCNT_SIG_CH1_IN0_IDX + 4 * unit);
int ctrl_sig_index = (channel == 0 ? PCNT_CTRL_CH0_IN0_IDX + 4 * unit : PCNT_CTRL_CH1_IN0_IDX + 4 * unit);
if(pulse_io >= 0) {
PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[pulse_io], PIN_FUNC_GPIO);
gpio_set_direction(pulse_io, GPIO_MODE_INPUT);
gpio_set_pull_mode(pulse_io, GPIO_PULLUP_ONLY);
gpio_matrix_in(pulse_io, input_sig_index, 0);
}
if(ctrl_io >= 0) {
PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[ctrl_io], PIN_FUNC_GPIO);
gpio_set_direction(ctrl_io, GPIO_MODE_INPUT);
gpio_set_pull_mode(ctrl_io, GPIO_PULLUP_ONLY);
gpio_matrix_in(ctrl_io, ctrl_sig_index, 0);
}

Is this the minimum setup to start playing with the Counter?

Hi i have done some further test with the hardware counter and i think your documentation is not clear.

Your driver may also be affected. Have you tested that your code will clear a counter that is not zero?

esp_err_t pcnt_counter_clear(pcnt_unit_t pcnt_unit)
{
PCNT_CHECK(pcnt_unit < PCNT_UNIT_MAX, PCNT_UNIT_ERR_STR, ESP_ERR_INVALID_ARG);
PCNT_ENTER_CRITICAL(&pcnt_spinlock);
PCNT.ctrl.val &= (~(BIT(PCNT_PLUS_CNT_RST_U0_S + (pcnt_unit * 2))));
PCNT_EXIT_CRITICAL(&pcnt_spinlock);
return ESP_OK;
}


Register 8.9: PCNT_CTRL_REG (0x00b0)
PCNT_CNT_PAUSE_Un Set this bit to freeze unit n’s counter. (R/W)
PCNT_PLUS_CNT_RST_Un Set this bit to clear & stop unit n’s counter. Clear the bit to start counting (if not paused) (R/W) (This bit is initially set)

This should clear the counter:

esp_err_t pcnt_counter_clear(pcnt_unit_t pcnt_unit)
{
PCNT_CHECK(pcnt_unit < PCNT_UNIT_MAX, PCNT_UNIT_ERR_STR, ESP_ERR_INVALID_ARG);
PCNT_ENTER_CRITICAL(&pcnt_spinlock);
PCNT.ctrl.val |= (BIT(PCNT_PLUS_CNT_RST_U0_S + (pcnt_unit * 2)));
// may be a delay here ...
PCNT.ctrl.val &= (~(BIT(PCNT_PLUS_CNT_RST_U0_S + (pcnt_unit * 2))));
PCNT_EXIT_CRITICAL(&pcnt_spinlock);
return ESP_OK;
}

I've also found that the current implementation of pcnt_counter_clear is not working. If I call the function the counter will not be reset to zero. But with the code SpenZerX suggested it's working.

Btw: I found that the initialization of the counter can't be done with pcnt_set_mode and pcnt_set_pin. I though that only these two calls can initialize the counter but that's not working because the call to periph_module_enable(PERIPH_PCNT_MODULE) should also be done.

Maybe someone from the espressif team could fix the pcnt_counter_clear api...

THANK YOU SpenZerX for posting that code! I was tearing my hair out trying to get that PCNT peripheral to clear its counter.

Espressif, please get this fix integrated into the ESP-IDF.

Joster, Superkurt: Any solution with PCNT and pulse Counting of esp32.

Thanks,
Ondrej

SpenZerX wrote:This should clear the counter:

esp_err_t pcnt_counter_clear(pcnt_unit_t pcnt_unit)
{
PCNT_CHECK(pcnt_unit < PCNT_UNIT_MAX, PCNT_UNIT_ERR_STR, ESP_ERR_INVALID_ARG);
PCNT_ENTER_CRITICAL(&pcnt_spinlock);
PCNT.ctrl.val |= (BIT(PCNT_PLUS_CNT_RST_U0_S + (pcnt_unit * 2)));
// may be a delay here ...
PCNT.ctrl.val &= (~(BIT(PCNT_PLUS_CNT_RST_U0_S + (pcnt_unit * 2))));
PCNT_EXIT_CRITICAL(&pcnt_spinlock);
return ESP_OK;
}

Thank you!
That saved tons of time.
Cheers

SpenZerX First post was, "Minimum requirements to start the Hardware Counter" then went to resetting the counter,, But can someone please confirm that his code in the 1 post is the Minimum requirements.... to evaluate the pulse counter.. Any thoughts would be appreciated.. Thank's..