Esempio n. 1
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/// \method read_timed(buf, timer)
///
/// Read analog values into `buf` at a rate set by the `timer` object.
///
/// `buf` can be bytearray or array.array for example.  The ADC values have
/// 12-bit resolution and are stored directly into `buf` if its element size is
/// 16 bits or greater.  If `buf` has only 8-bit elements (eg a bytearray) then
/// the sample resolution will be reduced to 8 bits.
///
/// `timer` should be a Timer object, and a sample is read each time the timer
/// triggers.  The timer must already be initialised and running at the desired
/// sampling frequency.
///
/// To support previous behaviour of this function, `timer` can also be an
/// integer which specifies the frequency (in Hz) to sample at.  In this case
/// Timer(6) will be automatically configured to run at the given frequency.
///
/// Example using a Timer object (preferred way):
///
///     adc = pyb.ADC(pyb.Pin.board.X19)    # create an ADC on pin X19
///     tim = pyb.Timer(6, freq=10)         # create a timer running at 10Hz
///     buf = bytearray(100)                # creat a buffer to store the samples
///     adc.read_timed(buf, tim)            # sample 100 values, taking 10s
///
/// Example using an integer for the frequency:
///
///     adc = pyb.ADC(pyb.Pin.board.X19)    # create an ADC on pin X19
///     buf = bytearray(100)                # create a buffer of 100 bytes
///     adc.read_timed(buf, 10)             # read analog values into buf at 10Hz
///                                         #   this will take 10 seconds to finish
///     for val in buf:                     # loop over all values
///         print(val)                      # print the value out
///
/// This function does not allocate any memory.
STATIC mp_obj_t adc_read_timed(mp_obj_t self_in, mp_obj_t buf_in, mp_obj_t freq_in) {
    pyb_obj_adc_t *self = self_in;

    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(buf_in, &bufinfo, MP_BUFFER_WRITE);
    size_t typesize = mp_binary_get_size('@', bufinfo.typecode, NULL);

    TIM_HandleTypeDef *tim;
    #if defined(TIM6)
    if (mp_obj_is_integer(freq_in)) {
        // freq in Hz given so init TIM6 (legacy behaviour)
        tim = timer_tim6_init(mp_obj_get_int(freq_in));
        HAL_TIM_Base_Start(tim);
    } else
    #endif
    {
        // use the supplied timer object as the sampling time base
        tim = pyb_timer_get_handle(freq_in);
    }

    // configure the ADC channel
    adc_config_channel(&self->handle, self->channel);

    // This uses the timer in polling mode to do the sampling
    // TODO use DMA

    uint nelems = bufinfo.len / typesize;
    for (uint index = 0; index < nelems; index++) {
        // Wait for the timer to trigger so we sample at the correct frequency
        while (__HAL_TIM_GET_FLAG(tim, TIM_FLAG_UPDATE) == RESET) {
        }
        __HAL_TIM_CLEAR_FLAG(tim, TIM_FLAG_UPDATE);

        if (index == 0) {
            // for the first sample we need to turn the ADC on
            HAL_ADC_Start(&self->handle);
        } else {
            // for subsequent samples we can just set the "start sample" bit
#if defined(STM32F4) || defined(STM32F7)
            ADCx->CR2 |= (uint32_t)ADC_CR2_SWSTART;
#elif defined(STM32L4)
            SET_BIT(ADCx->CR, ADC_CR_ADSTART);
#else
            #error Unsupported processor
#endif
        }

        // wait for sample to complete
        #define READ_TIMED_TIMEOUT (10) // in ms
        adc_wait_for_eoc_or_timeout(READ_TIMED_TIMEOUT);

        // read value
        uint value = ADCx->DR;

        // store value in buffer
        if (typesize == 1) {
            value >>= 4;
        }
        mp_binary_set_val_array_from_int(bufinfo.typecode, bufinfo.buf, index, value);
    }
Esempio n. 2
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/// \method read()
/// Read the value on the analog pin and return it.  The returned value
/// will be between 0 and 4095.
STATIC mp_obj_t adc_read(mp_obj_t self_in) {
    pyb_obj_adc_t *self = self_in;

    adc_config_channel(&self->handle, self->channel);
    uint32_t data = adc_read_channel(&self->handle);
    return mp_obj_new_int(data);
}
Esempio n. 3
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/// \method read_timed(buf, freq)
/// Read analog values into the given buffer at the given frequency. Buffer
/// can be bytearray or array.array for example. If a buffer with 8-bit elements
/// is used, sample resolution will be reduced to 8 bits.
///
/// Example:
///
///     adc = pyb.ADC(pyb.Pin.board.X19)    # create an ADC on pin X19
///     buf = bytearray(100)                # create a buffer of 100 bytes
///     adc.read_timed(buf, 10)             # read analog values into buf at 10Hz
///                                         #   this will take 10 seconds to finish
///     for val in buf:                     # loop over all values
///         print(val)                      # print the value out
///
/// This function does not allocate any memory.
STATIC mp_obj_t adc_read_timed(mp_obj_t self_in, mp_obj_t buf_in, mp_obj_t freq_in) {
    pyb_obj_adc_t *self = self_in;

    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(buf_in, &bufinfo, MP_BUFFER_WRITE);
    int typesize = mp_binary_get_size('@', bufinfo.typecode, NULL);

    // Init TIM6 at the required frequency (in Hz)
    timer_tim6_init(mp_obj_get_int(freq_in));

    // Start timer
    HAL_TIM_Base_Start(&TIM6_Handle);

    // This uses the timer in polling mode to do the sampling
    // We could use DMA, but then we can't convert the values correctly for the buffer
    adc_config_channel(self);
    for (uint index = 0; index < bufinfo.len; index++) {
        // Wait for the timer to trigger
        while (__HAL_TIM_GET_FLAG(&TIM6_Handle, TIM_FLAG_UPDATE) == RESET) {
        }
        __HAL_TIM_CLEAR_FLAG(&TIM6_Handle, TIM_FLAG_UPDATE);
        uint value = adc_read_channel(&self->handle);
        if (typesize == 1) {
            value >>= 4;
        }
        mp_binary_set_val_array_from_int(bufinfo.typecode, bufinfo.buf, index, value);
    }
Esempio n. 4
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/// \method read_timed(buf, freq)
/// Read analog values into the given buffer at the given frequency. Buffer
/// can be bytearray or array.array for example. If a buffer with 8-bit elements
/// is used, sample resolution will be reduced to 8 bits.
///
/// Example:
///
///     adc = pyb.ADC(pyb.Pin.board.X19)    # create an ADC on pin X19
///     buf = bytearray(100)                # create a buffer of 100 bytes
///     adc.read_timed(buf, 10)             # read analog values into buf at 10Hz
///                                         #   this will take 10 seconds to finish
///     for val in buf:                     # loop over all values
///         print(val)                      # print the value out
///
/// This function does not allocate any memory.
STATIC mp_obj_t adc_read_timed(mp_obj_t self_in, mp_obj_t buf_in, mp_obj_t freq_in) {
    pyb_obj_adc_t *self = self_in;

    mp_buffer_info_t bufinfo;
    mp_get_buffer_raise(buf_in, &bufinfo, MP_BUFFER_WRITE);
    int typesize = mp_binary_get_size('@', bufinfo.typecode, NULL);

    // Init TIM6 at the required frequency (in Hz)
    timer_tim6_init(mp_obj_get_int(freq_in));

    // Start timer
    HAL_TIM_Base_Start(&TIM6_Handle);

    // configure the ADC channel
    adc_config_channel(self);

    // This uses the timer in polling mode to do the sampling
    // TODO use DMA

    uint nelems = bufinfo.len / typesize;
    for (uint index = 0; index < nelems; index++) {
        // Wait for the timer to trigger so we sample at the correct frequency
        while (__HAL_TIM_GET_FLAG(&TIM6_Handle, TIM_FLAG_UPDATE) == RESET) {
        }
        __HAL_TIM_CLEAR_FLAG(&TIM6_Handle, TIM_FLAG_UPDATE);

        if (index == 0) {
            // for the first sample we need to turn the ADC on
            HAL_ADC_Start(&self->handle);
        } else {
            // for subsequent samples we can just set the "start sample" bit
            ADCx->CR2 |= (uint32_t)ADC_CR2_SWSTART;
        }

        // wait for sample to complete
        uint32_t tickstart = HAL_GetTick();
        while ((ADCx->SR & ADC_FLAG_EOC) != ADC_FLAG_EOC) {
            #define READ_TIMED_TIMEOUT (10) // in ms
            if (((HAL_GetTick() - tickstart ) > READ_TIMED_TIMEOUT)) {
                break; // timeout
            }
        }

        // read value
        uint value = ADCx->DR;

        // store value in buffer
        if (typesize == 1) {
            value >>= 4;
        }
        mp_binary_set_val_array_from_int(bufinfo.typecode, bufinfo.buf, index, value);
    }
Esempio n. 5
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STATIC uint32_t adc_config_and_read_channel(ADC_HandleTypeDef *adcHandle, uint32_t channel) {
    adc_config_channel(adcHandle, channel);
    uint32_t raw_value = adc_read_channel(adcHandle);

    #if defined(STM32F4) || defined(STM32F7)
    // ST docs say that (at least on STM32F42x and STM32F43x), VBATE must
    // be disabled when TSVREFE is enabled for TEMPSENSOR and VREFINT
    // conversions to work.  VBATE is enabled by the above call to read
    // the channel, and here we disable VBATE so a subsequent call for
    // TEMPSENSOR or VREFINT works correctly.
    if (channel == ADC_CHANNEL_VBAT) {
        ADC->CCR &= ~ADC_CCR_VBATE;
    }
    #endif

    return raw_value;
}