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Update phase to match official docs.

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Peter Hinch 2018-04-18 09:42:58 +01:00
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4
README.md
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@ -69,7 +69,7 @@ pull definition to provide a pull up or pull down as required.
The `encoder.portable.py` version should work on all MicroPython platforms.
Tested on ESP8266. Note that interrupt latency on the ESP8266 limits
performance. ESP32 is similar.
performance. ESP32 has similar limitations.
# A pseudo random number generator
@ -107,7 +107,7 @@ Linux installation and having to compile the Unix build of MicroPython.
# Measurement of relative timing and phase of fast analog signals
This describes ways of using the Pyboard to perform precision measurements of
analog signals of up to around 36KHz. It is documented [here](./phase/README.md).
analog signals of up to around 50KHz. It is documented [here](./phase/README.md).
# A design for a hardware power meter

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phase/README.md
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@ -1,92 +1,41 @@
# Measurement of relative timing and phase of fast analog signals
# 1. Introduction
The principal purpose of this application note is to describe a technique for
measuring the relative phase of a pair of sinsusoidal signals over the full
range of 2π radians (360°). This is known as quadrature detection; while
ancient history to radio engineers the method may be unfamiliar to those from
a programming background.
## 1.1 Measurement of relative timing and phase of analog signals
As of 11th April 2018 the Pyboard firmware has been enhanced to enable multiple
ADC channels to be read in a similar way to the existing `read_timed` method.
At each timer tick a reading is taken from each ADC in very quick succession.
This enables the relative timing or phase of relatively fast signals to be
measured.
ADC channels to be read in response to a timer tick. At each tick a reading is
taken from each ADC in quick succession. This enables the relative timing or
phase of signals to be measured. This is facilitated by the static method
`ADC.read_timed_multi` which is documented
[here](http://docs.micropython.org/en/latest/pyboard/library/pyb.ADC.html).
The ability to perform such measurements substantially increases the potential
application areas of the Pyboard, supporting precision measurements of signals
into the ultrasonic range. Applications such as ultrasonic rangefinders come to
mind. With two or more microphones it may be feasible to produce an ultrasonic
active sonar capable of providing directional and distance information for
multiple targets.
into the ultrasonic range. Applications such as ultrasonic rangefinders may be
practicable. With two or more microphones it may be feasible to produce an
ultrasonic active sonar capable of providing directional and distance
information for multiple targets.
I have used it to build an electrical network analyser which yields accurate
gain and phase plots of signals up to 36KHz.
# 1. Staticmethod ADC.read_timed_multi
The following is based on the documentation changes in the above PR.
Call pattern:
```python
from pyb import ADC
ok = ADC.read_timed_multi((adcx, adcy, ...), (bufx, bufy, ...), timer)
```
This is a static method. It can be used to extract relative timing or phase
data from multiple ADC's.
It reads analog values from multiple ADCs into buffers at a rate set by the
`timer` object. Each time the timer triggers a sample is rapidly read from each
ADC in turn.
ADC and buffer instances are passed in tuples with each ADC having an
associated buffer. All buffers must be of the same type and length and the
number of buffers must equal the number of ADC's.
Buffers must be `bytearray` or `array.array` instances. The ADC values have
12-bit resolution and are stored directly into the buffer if its element size
is 16 bits or greater. If buffers have only 8-bit elements (i.e. a bytearray)
then the sample resolution will be reduced to 8 bits.
`timer` must be a Timer object. The timer must already be initialised and
running at the desired sampling frequency.
Example reading 3 ADC's:
```python
import pyb
import array
adc0 = pyb.ADC(pyb.Pin.board.X1) # Create ADC's
adc1 = pyb.ADC(pyb.Pin.board.X2)
adc2 = pyb.ADC(pyb.Pin.board.X3)
tim = pyb.Timer(8, freq=100) # Create timer
rx0 = array.array('H', (0 for i in range(100))) # ADC buffers of
rx1 = array.array('H', (0 for i in range(100))) # 100 16-bit words
rx2 = array.array('H', (0 for i in range(100)))
# read analog values into buffers at 100Hz (takes one second)
pyb.ADC.read_timed_multi((adc0, adc1, adc2), (rx0, rx1, rx2), tim)
for n in range(len(rx0)):
print(rx0[n], rx1[n], rx2[n])
```
This function does not allocate any memory. It has blocking behaviour: it does
not return to the calling program until the buffers are full.
The function returns `True` if all samples were acquired with correct timing.
At high sample rates the time taken to acquire a set of samples can exceed the
timer period. In this case the function returns `False`, indicating a loss of
precision in the sample interval. In extreme cases samples may be missed.
The maximum rate depends on factors including the data width and the number of
ADC's being read. In testing two ADC's were sampled at 12 bit precision and at
a timer rate of 210KHz without overrun. At high sample rates disabling
interrupts for the duration can reduce the risk of sporadic data loss.
gain and phase (+-5°) plots of signals up to 40KHz.
# 2 Applications
## 2.1 Measurements of relative timing
In practice `ADC.read_timed_multi` reads each ADC in turn. This implies a delay
between each reading. This was measured at 3.236μs on a Pyboard V1.1 and can be
used to compensate any measurements taken.
between each reading. This was measured at 3.24μs on a Pyboard V1.1. The
measured value can be used to compensate any readings taken.
## 2.2 Phase measurements
### 2.2.1 The phase sensitive detector
### 2.2.1 The quadrature detector
The principle of a phase sensitive detector (applicable to linear and sampled
data systems) is based on multiplying the two signals and low pass filtering
@ -107,12 +56,12 @@ phase of the two signals. The second is an AC component at twice the incoming
frequency. So if the product signal is passed through a low pass filter the
right hand term disappears leaving only 0.5cos(-ϕ).
Where the frequency is known ideal filtering may be achieved simply, by
averaging over an integer number of cycles.
Where the frequency is known the filtering may be achieved simply by averaging
over an integer number of cycles.
For the above to produce accurate phase measurements the amplitudes of the two
signals must be normalised to 1. Alternatively the amplitudes should be
measured and the resultant DC value divided by their product.
signals must be normalised to 1. Alternatively the amplitudes may be measured
and the DC phase value divided by their product.
Because cos ϕ = cos -ϕ this can only detect phase angles over a range of π
radians. To achieve detection over the full 2π range a second product detector
@ -150,11 +99,12 @@ accurately measure the phase difference between an outgoing sinewave produced
by `DAC.write_timed` and an incoming response signal. For application reasons
`DAC.write_timed` runs continuously. Its output feeds one ADC and the incoming
signal feeds another. The ADC's are fed from matched hardware anti-aliasing
filters.
filters; the matched characteristic ensures that any phase shift in the filters
cancels out.
Because the frequency is known the ADC sampling rate is chosen so that an
integer number of cycles are captured. This enables simple averaging to be used
to remove the double frequency component.
integer number of cycles are captured. Thus averaging is used to remove the
double frequency component.
The function `demod()` returns the phase difference in radians. The sample
arrays are globals `bufout` and `bufin`. The `freq` arg is the frequency and is
@ -199,6 +149,7 @@ def demod(freq, nsamples):
sum_quad /= (buflen * 0.5)
c = sum_norm + 1j * sum_quad # Create the complex phasor
# Apply phase compensation measured at 3.236μs
c *= 1 - 2j * pi * freq * 3.236e-6 # very close approximation
theta = 2 * pi * freq * 3.236e-6
c *= cos(theta) - 1j * sin(theta)
return cmath.phase(c)
```

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phase/adc.c
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@ -1,825 +0,0 @@
/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 Damien P. George
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdio.h>
#include <string.h>
#include "py/runtime.h"
#include "py/binary.h"
#include "py/mphal.h"
#include "adc.h"
#include "pin.h"
#include "genhdr/pins.h"
#include "timer.h"
#if MICROPY_HW_ENABLE_ADC
/// \moduleref pyb
/// \class ADC - analog to digital conversion: read analog values on a pin
///
/// Usage:
///
/// adc = pyb.ADC(pin) # create an analog object from a pin
/// val = adc.read() # read an analog value
///
/// adc = pyb.ADCAll(resolution) # creale an ADCAll object
/// val = adc.read_channel(channel) # read the given channel
/// val = adc.read_core_temp() # read MCU temperature
/// val = adc.read_core_vbat() # read MCU VBAT
/// val = adc.read_core_vref() # read MCU VREF
/* ADC defintions */
#define ADCx (ADC1)
#define ADCx_CLK_ENABLE __HAL_RCC_ADC1_CLK_ENABLE
#define ADC_NUM_CHANNELS (19)
#if defined(MCU_SERIES_F4)
#define ADC_FIRST_GPIO_CHANNEL (0)
#define ADC_LAST_GPIO_CHANNEL (15)
#define ADC_CAL_ADDRESS (0x1fff7a2a)
#define ADC_CAL1 ((uint16_t*)(ADC_CAL_ADDRESS + 2))
#define ADC_CAL2 ((uint16_t*)(ADC_CAL_ADDRESS + 4))
#elif defined(MCU_SERIES_F7)
#define ADC_FIRST_GPIO_CHANNEL (0)
#define ADC_LAST_GPIO_CHANNEL (15)
#if defined(STM32F722xx) || defined(STM32F723xx) || \
defined(STM32F732xx) || defined(STM32F733xx)
#define ADC_CAL_ADDRESS (0x1ff07a2a)
#else
#define ADC_CAL_ADDRESS (0x1ff0f44a)
#endif
#define ADC_CAL1 ((uint16_t*)(ADC_CAL_ADDRESS + 2))
#define ADC_CAL2 ((uint16_t*)(ADC_CAL_ADDRESS + 4))
#elif defined(MCU_SERIES_L4)
#define ADC_FIRST_GPIO_CHANNEL (1)
#define ADC_LAST_GPIO_CHANNEL (16)
#define ADC_CAL_ADDRESS (0x1fff75aa)
#define ADC_CAL1 ((uint16_t*)(ADC_CAL_ADDRESS - 2))
#define ADC_CAL2 ((uint16_t*)(ADC_CAL_ADDRESS + 0x20))
#else
#error Unsupported processor
#endif
#if defined(STM32F405xx) || defined(STM32F415xx) || \
defined(STM32F407xx) || defined(STM32F417xx) || \
defined(STM32F401xC) || defined(STM32F401xE) || \
defined(STM32F411xE)
#define VBAT_DIV (2)
#elif defined(STM32F427xx) || defined(STM32F429xx) || \
defined(STM32F437xx) || defined(STM32F439xx) || \
defined(STM32F722xx) || defined(STM32F723xx) || \
defined(STM32F732xx) || defined(STM32F733xx) || \
defined(STM32F746xx) || defined(STM32F767xx) || \
defined(STM32F769xx) || defined(STM32F446xx)
#define VBAT_DIV (4)
#elif defined(STM32L475xx) || defined(STM32L476xx)
#define VBAT_DIV (3)
#else
#error Unsupported processor
#endif
/* Core temperature sensor definitions */
#define CORE_TEMP_V25 (943) /* (0.76v/3.3v)*(2^ADC resoultion) */
#define CORE_TEMP_AVG_SLOPE (3) /* (2.5mv/3.3v)*(2^ADC resoultion) */
// scale and calibration values for VBAT and VREF
#define ADC_SCALE (3.3f / 4095)
#define VREFIN_CAL ((uint16_t *)ADC_CAL_ADDRESS)
typedef struct _pyb_obj_adc_t {
mp_obj_base_t base;
mp_obj_t pin_name;
int channel;
ADC_HandleTypeDef handle;
} pyb_obj_adc_t;
// convert user-facing channel number into internal channel number
static inline uint32_t adc_get_internal_channel(uint32_t channel) {
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
// on F4 and F7 MCUs we want channel 16 to always be the TEMPSENSOR
// (on some MCUs ADC_CHANNEL_TEMPSENSOR=16, on others it doesn't)
if (channel == 16) {
channel = ADC_CHANNEL_TEMPSENSOR;
}
#endif
return channel;
}
STATIC bool is_adcx_channel(int channel) {
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
return IS_ADC_CHANNEL(channel);
#elif defined(MCU_SERIES_L4)
ADC_HandleTypeDef handle;
handle.Instance = ADCx;
return IS_ADC_CHANNEL(&handle, channel);
#else
#error Unsupported processor
#endif
}
STATIC void adc_wait_for_eoc_or_timeout(int32_t timeout) {
uint32_t tickstart = HAL_GetTick();
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
while ((ADCx->SR & ADC_FLAG_EOC) != ADC_FLAG_EOC) {
#elif defined(MCU_SERIES_L4)
while (READ_BIT(ADCx->ISR, ADC_FLAG_EOC) != ADC_FLAG_EOC) {
#else
#error Unsupported processor
#endif
if (((HAL_GetTick() - tickstart ) > timeout)) {
break; // timeout
}
}
}
STATIC void adcx_clock_enable(void) {
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
ADCx_CLK_ENABLE();
#elif defined(MCU_SERIES_L4)
__HAL_RCC_ADC_CLK_ENABLE();
#else
#error Unsupported processor
#endif
}
STATIC void adc_init_single(pyb_obj_adc_t *adc_obj) {
if (!is_adcx_channel(adc_obj->channel)) {
return;
}
if (ADC_FIRST_GPIO_CHANNEL <= adc_obj->channel && adc_obj->channel <= ADC_LAST_GPIO_CHANNEL) {
// Channels 0-16 correspond to real pins. Configure the GPIO pin in
// ADC mode.
const pin_obj_t *pin = pin_adc1[adc_obj->channel];
mp_hal_gpio_clock_enable(pin->gpio);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.Pin = pin->pin_mask;
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
GPIO_InitStructure.Mode = GPIO_MODE_ANALOG;
#elif defined(MCU_SERIES_L4)
GPIO_InitStructure.Mode = GPIO_MODE_ANALOG_ADC_CONTROL;
#else
#error Unsupported processor
#endif
GPIO_InitStructure.Pull = GPIO_NOPULL;
HAL_GPIO_Init(pin->gpio, &GPIO_InitStructure);
}
adcx_clock_enable();
ADC_HandleTypeDef *adcHandle = &adc_obj->handle;
adcHandle->Instance = ADCx;
adcHandle->Init.ContinuousConvMode = DISABLE;
adcHandle->Init.DiscontinuousConvMode = DISABLE;
adcHandle->Init.NbrOfDiscConversion = 0;
adcHandle->Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
adcHandle->Init.DataAlign = ADC_DATAALIGN_RIGHT;
adcHandle->Init.NbrOfConversion = 1;
adcHandle->Init.DMAContinuousRequests = DISABLE;
adcHandle->Init.Resolution = ADC_RESOLUTION_12B;
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
adcHandle->Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV2;
adcHandle->Init.ScanConvMode = DISABLE;
adcHandle->Init.ExternalTrigConv = ADC_EXTERNALTRIGCONV_T1_CC1;
adcHandle->Init.EOCSelection = DISABLE;
#elif defined(MCU_SERIES_L4)
adcHandle->Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV1;
adcHandle->Init.ScanConvMode = ADC_SCAN_DISABLE;
adcHandle->Init.EOCSelection = ADC_EOC_SINGLE_CONV;
adcHandle->Init.ExternalTrigConv = ADC_SOFTWARE_START;
adcHandle->Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
adcHandle->Init.LowPowerAutoWait = DISABLE;
adcHandle->Init.Overrun = ADC_OVR_DATA_PRESERVED;
adcHandle->Init.OversamplingMode = DISABLE;
#else
#error Unsupported processor
#endif
HAL_ADC_Init(adcHandle);
#if defined(MCU_SERIES_L4)
ADC_MultiModeTypeDef multimode;
multimode.Mode = ADC_MODE_INDEPENDENT;
if (HAL_ADCEx_MultiModeConfigChannel(adcHandle, &multimode) != HAL_OK)
{
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "Can not set multimode on ADC1 channel: %d", adc_obj->channel));
}
#endif
}
STATIC void adc_config_channel(ADC_HandleTypeDef *adc_handle, uint32_t channel) {
ADC_ChannelConfTypeDef sConfig;
sConfig.Channel = channel;
sConfig.Rank = 1;
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
sConfig.SamplingTime = ADC_SAMPLETIME_15CYCLES;
#elif defined(MCU_SERIES_L4)
sConfig.SamplingTime = ADC_SAMPLETIME_12CYCLES_5;
sConfig.SingleDiff = ADC_SINGLE_ENDED;
sConfig.OffsetNumber = ADC_OFFSET_NONE;
#else
#error Unsupported processor
#endif
sConfig.Offset = 0;
HAL_ADC_ConfigChannel(adc_handle, &sConfig);
}
STATIC uint32_t adc_read_channel(ADC_HandleTypeDef *adcHandle) {
uint32_t rawValue = 0;
HAL_ADC_Start(adcHandle);
if (HAL_ADC_PollForConversion(adcHandle, 10) == HAL_OK
&& (HAL_ADC_GetState(adcHandle) & HAL_ADC_STATE_REG_EOC) == HAL_ADC_STATE_REG_EOC) {
rawValue = HAL_ADC_GetValue(adcHandle);
}
HAL_ADC_Stop(adcHandle);
return rawValue;
}
/******************************************************************************/
/* MicroPython bindings : adc object (single channel) */
STATIC void adc_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
pyb_obj_adc_t *self = self_in;
mp_print_str(print, "<ADC on ");
mp_obj_print_helper(print, self->pin_name, PRINT_STR);
mp_printf(print, " channel=%lu>", self->channel);
}
/// \classmethod \constructor(pin)
/// Create an ADC object associated with the given pin.
/// This allows you to then read analog values on that pin.
STATIC mp_obj_t adc_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
// check number of arguments
mp_arg_check_num(n_args, n_kw, 1, 1, false);
// 1st argument is the pin name
mp_obj_t pin_obj = args[0];
uint32_t channel;
if (MP_OBJ_IS_INT(pin_obj)) {
channel = adc_get_internal_channel(mp_obj_get_int(pin_obj));
} else {
const pin_obj_t *pin = pin_find(pin_obj);
if ((pin->adc_num & PIN_ADC1) == 0) {
// No ADC1 function on that pin
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "pin %q does not have ADC capabilities", pin->name));
}
channel = pin->adc_channel;
}
if (!is_adcx_channel(channel)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "not a valid ADC Channel: %d", channel));
}
if (ADC_FIRST_GPIO_CHANNEL <= channel && channel <= ADC_LAST_GPIO_CHANNEL) {
// these channels correspond to physical GPIO ports so make sure they exist
if (pin_adc1[channel] == NULL) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
"channel %d not available on this board", channel));
}
}
pyb_obj_adc_t *o = m_new_obj(pyb_obj_adc_t);
memset(o, 0, sizeof(*o));
o->base.type = &pyb_adc_type;
o->pin_name = pin_obj;
o->channel = channel;
adc_init_single(o);
return o;
}
/// \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);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_read_obj, adc_read);
/// \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(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
ADCx->CR2 |= (uint32_t)ADC_CR2_SWSTART;
#elif defined(MCU_SERIES_L4)
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);
}
// turn the ADC off
HAL_ADC_Stop(&self->handle);
#if defined(TIM6)
if (mp_obj_is_integer(freq_in)) {
// stop timer if we initialised TIM6 in this function (legacy behaviour)
HAL_TIM_Base_Stop(tim);
}
#endif
return mp_obj_new_int(bufinfo.len);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(adc_read_timed_obj, adc_read_timed);
/// \method read_timed_multi((adcx, adcy, ...), (bufx, bufy, ...), timer)
///
/// Read analog values from multiple ADC's into `buf` at a rate set by the
/// `timer` object. Each ADC has its own buffer. Can be used to extract
/// relative timing or phase data. All buffers must be of the same type and
/// length.
///
/// Buffers 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 buffers have 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 from each ADC is read each
/// time the timer triggers. The timer must already be initialised and running
/// at the desired sampling frequency.
///
/// Example reading three ADC's:
///
/// adc0 = pyb.ADC(pyb.Pin.board.X1) # Create ADC's
/// adc1 = pyb.ADC(pyb.Pin.board.X2)
/// adc2 = pyb.ADC(pyb.Pin.board.X3)
/// tim = pyb.Timer(8, freq=100) # Create timer
/// rx0 = array.array('H', (0 for i in range(100))) # ADC buffers of
/// rx1 = array.array('H', (0 for i in range(100))) # 100 16-bit words
/// rx2 = array.array('H', (0 for i in range(100)))
/// # read analog values into buf at 100Hz (takes one second)
/// pyb.ADC.read_timed_multi((adc0, adc1, adc2), (rx0, rx1, rx2), tim)
/// for n in range(len(rx0)):
/// print(rx0[n], rx1[n], rx2[n])
///
/// This function does not allocate any memory.
STATIC mp_obj_t adc_read_timed_multi(mp_obj_t adc_array_in, mp_obj_t buf_array_in, mp_obj_t tim_in) {
size_t nadcs, nbufs;
mp_obj_t *adc_array, *buf_array;
mp_obj_get_array(adc_array_in, &nadcs, &adc_array);
mp_obj_get_array(buf_array_in, &nbufs, &buf_array);
if (nadcs != nbufs) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
"length of buffer list and ADC list differ"));
}
if (nadcs < 1) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
"must specify at least 1 ADC"));
}
// Get buf for first ADC. Get word size. Check other buffers match.
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(buf_array[0], &bufinfo, MP_BUFFER_WRITE);
size_t typesize = mp_binary_get_size('@', bufinfo.typecode, NULL);
for (uint array_index = 0; array_index < nbufs; array_index++) {
mp_buffer_info_t bufinfo_curr;
mp_get_buffer_raise(buf_array[array_index], &bufinfo_curr, MP_BUFFER_WRITE);
if ((bufinfo.len != bufinfo_curr.len) || (bufinfo.typecode != bufinfo_curr.typecode)) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
"size and type of buffers must match"));
}
}
// use the supplied timer object as the sampling time base
TIM_HandleTypeDef *tim;
tim = pyb_timer_get_handle(tim_in);
// Start adc. This is slow so wait for it to start.
pyb_obj_adc_t *adc0 = adc_array[0];
adc_config_channel(&adc0->handle, adc0->channel);
HAL_ADC_Start(&adc0->handle);
// wait for sample to complete and discard
#define READ_TIMED_TIMEOUT (10) // in ms
adc_wait_for_eoc_or_timeout(READ_TIMED_TIMEOUT);
// read (and discard) value
uint value = ADCx->DR;
// Ensure first sample is on a timer tick
__HAL_TIM_CLEAR_FLAG(tim, TIM_FLAG_UPDATE);
while (__HAL_TIM_GET_FLAG(tim, TIM_FLAG_UPDATE) == RESET) {
}
__HAL_TIM_CLEAR_FLAG(tim, TIM_FLAG_UPDATE);
// Overrun check: assume success.
uint success = 1;
uint nelems = bufinfo.len / typesize;
for (uint elem_index = 0; elem_index < nelems; elem_index++) {
if (__HAL_TIM_GET_FLAG(tim, TIM_FLAG_UPDATE) != RESET) {
// Timer has already triggered.
success = 0;
} else {
// 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);
for (uint array_index = 0; array_index < nadcs; array_index++) {
pyb_obj_adc_t *adc = adc_array[array_index];
// configure the ADC channel
adc_config_channel(&adc->handle, adc->channel);
// for the first sample we need to turn the ADC on
// ADC is started: set the "start sample" bit
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
ADCx->CR2 |= (uint32_t)ADC_CR2_SWSTART;
#elif defined(MCU_SERIES_L4)
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
value = ADCx->DR;
// store values in buffer
if (typesize == 1) {
value >>= 4;
}
mp_buffer_info_t bufinfo_curr; // Get buf for current ADC
mp_get_buffer_raise(buf_array[array_index], &bufinfo_curr, MP_BUFFER_WRITE);
mp_binary_set_val_array_from_int(bufinfo_curr.typecode, bufinfo_curr.buf, elem_index, value);
}
}
// turn the ADC off
adc0 = adc_array[0];
HAL_ADC_Stop(&adc0->handle);
return mp_obj_new_bool(success);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(adc_read_timed_multi_fun_obj, adc_read_timed_multi);
//STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(adc_read_timed_multi_fun_obj, 3, 3, adc_read_timed_multi);
STATIC MP_DEFINE_CONST_STATICMETHOD_OBJ(adc_read_timed_multi_obj, MP_ROM_PTR(&adc_read_timed_multi_fun_obj));
STATIC const mp_rom_map_elem_t adc_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&adc_read_obj) },
{ MP_ROM_QSTR(MP_QSTR_read_timed), MP_ROM_PTR(&adc_read_timed_obj) },
{ MP_ROM_QSTR(MP_QSTR_read_timed_multi), MP_ROM_PTR(&adc_read_timed_multi_obj) },
};
STATIC MP_DEFINE_CONST_DICT(adc_locals_dict, adc_locals_dict_table);
const mp_obj_type_t pyb_adc_type = {
{ &mp_type_type },
.name = MP_QSTR_ADC,
.print = adc_print,
.make_new = adc_make_new,
.locals_dict = (mp_obj_dict_t*)&adc_locals_dict,
};
/******************************************************************************/
/* adc all object */
typedef struct _pyb_adc_all_obj_t {
mp_obj_base_t base;
ADC_HandleTypeDef handle;
} pyb_adc_all_obj_t;
void adc_init_all(pyb_adc_all_obj_t *adc_all, uint32_t resolution, uint32_t en_mask) {
switch (resolution) {
case 6: resolution = ADC_RESOLUTION_6B; break;
case 8: resolution = ADC_RESOLUTION_8B; break;
case 10: resolution = ADC_RESOLUTION_10B; break;
case 12: resolution = ADC_RESOLUTION_12B; break;
default:
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError,
"resolution %d not supported", resolution));
}
for (uint32_t channel = ADC_FIRST_GPIO_CHANNEL; channel <= ADC_LAST_GPIO_CHANNEL; ++channel) {
// only initialise those channels that are selected with the en_mask
if (en_mask & (1 << channel)) {
// Channels 0-16 correspond to real pins. Configure the GPIO pin in
// ADC mode.
const pin_obj_t *pin = pin_adc1[channel];
if (pin) {
mp_hal_gpio_clock_enable(pin->gpio);
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.Pin = pin->pin_mask;
GPIO_InitStructure.Mode = GPIO_MODE_ANALOG;
GPIO_InitStructure.Pull = GPIO_NOPULL;
HAL_GPIO_Init(pin->gpio, &GPIO_InitStructure);
}
}
}
adcx_clock_enable();
ADC_HandleTypeDef *adcHandle = &adc_all->handle;
adcHandle->Instance = ADCx;
adcHandle->Init.Resolution = resolution;
adcHandle->Init.ContinuousConvMode = DISABLE;
adcHandle->Init.DiscontinuousConvMode = DISABLE;
adcHandle->Init.NbrOfDiscConversion = 0;
adcHandle->Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
adcHandle->Init.DataAlign = ADC_DATAALIGN_RIGHT;
adcHandle->Init.NbrOfConversion = 1;
adcHandle->Init.DMAContinuousRequests = DISABLE;
adcHandle->Init.EOCSelection = DISABLE;
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
adcHandle->Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV2;
adcHandle->Init.ScanConvMode = DISABLE;
adcHandle->Init.ExternalTrigConv = ADC_EXTERNALTRIGCONV_T1_CC1;
#elif defined(MCU_SERIES_L4)
adcHandle->Init.ClockPrescaler = ADC_CLOCK_ASYNC_DIV2;
adcHandle->Init.ScanConvMode = ADC_SCAN_DISABLE;
adcHandle->Init.ExternalTrigConv = ADC_EXTERNALTRIG_T1_CC1;
adcHandle->Init.LowPowerAutoWait = DISABLE;
adcHandle->Init.Overrun = ADC_OVR_DATA_PRESERVED;
adcHandle->Init.OversamplingMode = DISABLE;
#else
#error Unsupported processor
#endif
HAL_ADC_Init(adcHandle);
}
uint32_t adc_config_and_read_channel(ADC_HandleTypeDef *adcHandle, uint32_t channel) {
adc_config_channel(adcHandle, channel);
return adc_read_channel(adcHandle);
}
int adc_get_resolution(ADC_HandleTypeDef *adcHandle) {
uint32_t res_reg = ADC_GET_RESOLUTION(adcHandle);
switch (res_reg) {
case ADC_RESOLUTION_6B: return 6;
case ADC_RESOLUTION_8B: return 8;
case ADC_RESOLUTION_10B: return 10;
}
return 12;
}
int adc_read_core_temp(ADC_HandleTypeDef *adcHandle) {
int32_t raw_value = adc_config_and_read_channel(adcHandle, ADC_CHANNEL_TEMPSENSOR);
// Note: constants assume 12-bit resolution, so we scale the raw value to
// be 12-bits.
raw_value <<= (12 - adc_get_resolution(adcHandle));
return ((raw_value - CORE_TEMP_V25) / CORE_TEMP_AVG_SLOPE) + 25;
}
#if MICROPY_PY_BUILTINS_FLOAT
// correction factor for reference value
STATIC volatile float adc_refcor = 1.0f;
float adc_read_core_temp_float(ADC_HandleTypeDef *adcHandle) {
int32_t raw_value = adc_config_and_read_channel(adcHandle, ADC_CHANNEL_TEMPSENSOR);
// constants assume 12-bit resolution so we scale the raw value to 12-bits
raw_value <<= (12 - adc_get_resolution(adcHandle));
float core_temp_avg_slope = (*ADC_CAL2 - *ADC_CAL1) / 80.0;
return (((float)raw_value * adc_refcor - *ADC_CAL1) / core_temp_avg_slope) + 30.0f;
}
float adc_read_core_vbat(ADC_HandleTypeDef *adcHandle) {
uint32_t raw_value = adc_config_and_read_channel(adcHandle, ADC_CHANNEL_VBAT);
// Note: constants assume 12-bit resolution, so we scale the raw value to
// be 12-bits.
raw_value <<= (12 - adc_get_resolution(adcHandle));
#if defined(MCU_SERIES_F4) || defined(MCU_SERIES_F7)
// 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.
ADC->CCR &= ~ADC_CCR_VBATE;
#endif
return raw_value * VBAT_DIV * ADC_SCALE * adc_refcor;
}
float adc_read_core_vref(ADC_HandleTypeDef *adcHandle) {
uint32_t raw_value = adc_config_and_read_channel(adcHandle, ADC_CHANNEL_VREFINT);
// Note: constants assume 12-bit resolution, so we scale the raw value to
// be 12-bits.
raw_value <<= (12 - adc_get_resolution(adcHandle));
// update the reference correction factor
adc_refcor = ((float)(*VREFIN_CAL)) / ((float)raw_value);
return (*VREFIN_CAL) * ADC_SCALE;
}
#endif
/******************************************************************************/
/* MicroPython bindings : adc_all object */
STATIC mp_obj_t adc_all_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
// check number of arguments
mp_arg_check_num(n_args, n_kw, 1, 2, false);
// make ADCAll object
pyb_adc_all_obj_t *o = m_new_obj(pyb_adc_all_obj_t);
o->base.type = &pyb_adc_all_type;
mp_int_t res = mp_obj_get_int(args[0]);
uint32_t en_mask = 0xffffffff;
if (n_args > 1) {
en_mask = mp_obj_get_int(args[1]);
}
adc_init_all(o, res, en_mask);
return o;
}
STATIC mp_obj_t adc_all_read_channel(mp_obj_t self_in, mp_obj_t channel) {
pyb_adc_all_obj_t *self = self_in;
uint32_t chan = adc_get_internal_channel(mp_obj_get_int(channel));
uint32_t data = adc_config_and_read_channel(&self->handle, chan);
return mp_obj_new_int(data);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(adc_all_read_channel_obj, adc_all_read_channel);
STATIC mp_obj_t adc_all_read_core_temp(mp_obj_t self_in) {
pyb_adc_all_obj_t *self = self_in;
#if MICROPY_PY_BUILTINS_FLOAT
float data = adc_read_core_temp_float(&self->handle);
return mp_obj_new_float(data);
#else
int data = adc_read_core_temp(&self->handle);
return mp_obj_new_int(data);
#endif
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_all_read_core_temp_obj, adc_all_read_core_temp);
#if MICROPY_PY_BUILTINS_FLOAT
STATIC mp_obj_t adc_all_read_core_vbat(mp_obj_t self_in) {
pyb_adc_all_obj_t *self = self_in;
float data = adc_read_core_vbat(&self->handle);
return mp_obj_new_float(data);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_all_read_core_vbat_obj, adc_all_read_core_vbat);
STATIC mp_obj_t adc_all_read_core_vref(mp_obj_t self_in) {
pyb_adc_all_obj_t *self = self_in;
float data = adc_read_core_vref(&self->handle);
return mp_obj_new_float(data);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_all_read_core_vref_obj, adc_all_read_core_vref);
STATIC mp_obj_t adc_all_read_vref(mp_obj_t self_in) {
pyb_adc_all_obj_t *self = self_in;
adc_read_core_vref(&self->handle);
return mp_obj_new_float(3.3 * adc_refcor);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(adc_all_read_vref_obj, adc_all_read_vref);
#endif
STATIC const mp_rom_map_elem_t adc_all_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_read_channel), MP_ROM_PTR(&adc_all_read_channel_obj) },
{ MP_ROM_QSTR(MP_QSTR_read_core_temp), MP_ROM_PTR(&adc_all_read_core_temp_obj) },
#if MICROPY_PY_BUILTINS_FLOAT
{ MP_ROM_QSTR(MP_QSTR_read_core_vbat), MP_ROM_PTR(&adc_all_read_core_vbat_obj) },
{ MP_ROM_QSTR(MP_QSTR_read_core_vref), MP_ROM_PTR(&adc_all_read_core_vref_obj) },
{ MP_ROM_QSTR(MP_QSTR_read_vref), MP_ROM_PTR(&adc_all_read_vref_obj) },
#endif
};
STATIC MP_DEFINE_CONST_DICT(adc_all_locals_dict, adc_all_locals_dict_table);
const mp_obj_type_t pyb_adc_all_type = {
{ &mp_type_type },
.name = MP_QSTR_ADCAll,
.make_new = adc_all_make_new,
.locals_dict = (mp_obj_dict_t*)&adc_all_locals_dict,
};
#endif // MICROPY_HW_ENABLE_ADC