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Add Arduino SAM compatible analogReadResolution and Non-Blocking ADC api
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connected to: espressif/arduino-esp32#220 and
espressif/arduino-esp32#161
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@me-no-dev
me-no-dev committed Mar 3, 2017
1 parent 8fb8478 commit eb46978
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Showing 2 changed files with 125 additions and 15 deletions.
100 changes: 86 additions & 14 deletions cores/esp32/esp32-hal-adc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,12 +28,16 @@ static uint8_t __analogCycles = 8;
static uint8_t __analogSamples = 0;//1 sample
static uint8_t __analogClockDiv = 1;

// Width of returned answer ()
static uint8_t __analogReturnedWidth = 12;

void __analogSetWidth(uint8_t bits){
if(bits < 9){
bits = 9;
} else if(bits > 12){
bits = 12;
}
__analogReturnedWidth = bits;
__analogWidth = bits - 9;
SET_PERI_REG_BITS(SENS_SAR_START_FORCE_REG, SENS_SAR1_BIT_WIDTH, __analogWidth, SENS_SAR1_BIT_WIDTH_S);
SET_PERI_REG_BITS(SENS_SAR_READ_CTRL_REG, SENS_SAR1_SAMPLE_BIT, __analogWidth, SENS_SAR1_SAMPLE_BIT_S);
Expand Down Expand Up @@ -124,14 +128,14 @@ void __analogSetPinAttenuation(uint8_t pin, adc_attenuation_t attenuation)
}
}

uint16_t IRAM_ATTR __analogRead(uint8_t pin)
{
bool IRAM_ATTR __adcAttachPin(uint8_t pin){

int8_t channel = digitalPinToAnalogChannel(pin);
if(channel < 0){
return 0;//not adc pin
return false;//not adc pin
}
int8_t pad = digitalPinToTouchChannel(pin);

int8_t pad = digitalPinToTouchChannel(pin);
if(pad >= 0){
uint32_t touch = READ_PERI_REG(SENS_SAR_TOUCH_ENABLE_REG);
if(touch & (1 << pad)){
Expand All @@ -149,22 +153,84 @@ uint16_t IRAM_ATTR __analogRead(uint8_t pin)
pinMode(pin, ANALOG);

__analogInit();
return true;
}

if(channel > 7){
channel -= 10;
bool IRAM_ATTR __adcStart(uint8_t pin){

SET_PERI_REG_BITS(SENS_SAR_MEAS_START2_REG, SENS_SAR2_EN_PAD, (1 << channel), SENS_SAR2_EN_PAD_S);
int8_t channel = digitalPinToAnalogChannel(pin);
if(channel < 0){
return false;//not adc pin
}

if(channel > 9){
channel -= 10;
CLEAR_PERI_REG_MASK(SENS_SAR_MEAS_START2_REG, SENS_MEAS2_START_SAR_M);
SET_PERI_REG_BITS(SENS_SAR_MEAS_START2_REG, SENS_SAR2_EN_PAD, (1 << channel), SENS_SAR2_EN_PAD_S);
SET_PERI_REG_MASK(SENS_SAR_MEAS_START2_REG, SENS_MEAS2_START_SAR_M);
while (GET_PERI_REG_MASK(SENS_SAR_MEAS_START2_REG, SENS_MEAS2_DONE_SAR) == 0) {}; //read done
return GET_PERI_REG_BITS2(SENS_SAR_MEAS_START2_REG, SENS_MEAS2_DATA_SAR, SENS_MEAS2_DATA_SAR_S);
} else {
CLEAR_PERI_REG_MASK(SENS_SAR_MEAS_START1_REG, SENS_MEAS1_START_SAR_M);
SET_PERI_REG_BITS(SENS_SAR_MEAS_START1_REG, SENS_SAR1_EN_PAD, (1 << channel), SENS_SAR1_EN_PAD_S);
SET_PERI_REG_MASK(SENS_SAR_MEAS_START1_REG, SENS_MEAS1_START_SAR_M);
}
return true;
}

bool IRAM_ATTR __adcBusy(uint8_t pin){

SET_PERI_REG_BITS(SENS_SAR_MEAS_START1_REG, SENS_SAR1_EN_PAD, (1 << channel), SENS_SAR1_EN_PAD_S);
CLEAR_PERI_REG_MASK(SENS_SAR_MEAS_START1_REG, SENS_MEAS1_START_SAR_M);
SET_PERI_REG_MASK(SENS_SAR_MEAS_START1_REG, SENS_MEAS1_START_SAR_M);
while (GET_PERI_REG_MASK(SENS_SAR_MEAS_START1_REG, SENS_MEAS1_DONE_SAR) == 0) {}; //read done
return GET_PERI_REG_BITS2(SENS_SAR_MEAS_START1_REG, SENS_MEAS1_DATA_SAR, SENS_MEAS1_DATA_SAR_S);
int8_t channel = digitalPinToAnalogChannel(pin);
if(channel < 0){
return false;//not adc pin
}

if(channel > 7){
return (GET_PERI_REG_MASK(SENS_SAR_MEAS_START2_REG, SENS_MEAS2_DONE_SAR) == 0);
}
return (GET_PERI_REG_MASK(SENS_SAR_MEAS_START1_REG, SENS_MEAS1_DONE_SAR) == 0);
}

uint16_t IRAM_ATTR __adcEnd(uint8_t pin)
{

uint16_t value = 0;
int8_t channel = digitalPinToAnalogChannel(pin);
if(channel < 0){
return 0;//not adc pin
}
if(channel > 7){
while (GET_PERI_REG_MASK(SENS_SAR_MEAS_START2_REG, SENS_MEAS2_DONE_SAR) == 0); //wait for conversion
value = GET_PERI_REG_BITS2(SENS_SAR_MEAS_START2_REG, SENS_MEAS2_DATA_SAR, SENS_MEAS2_DATA_SAR_S);
} else {
while (GET_PERI_REG_MASK(SENS_SAR_MEAS_START1_REG, SENS_MEAS1_DONE_SAR) == 0); //wait for conversion
value = GET_PERI_REG_BITS2(SENS_SAR_MEAS_START1_REG, SENS_MEAS1_DATA_SAR, SENS_MEAS1_DATA_SAR_S);
}

// Shift result if necessary
uint8_t from = __analogWidth + 9;
if (from == __analogReturnedWidth) {
return value;
}
if (from > __analogReturnedWidth) {
return value >> (from - __analogReturnedWidth);
}
return value << (__analogReturnedWidth - from);
}

uint16_t IRAM_ATTR __analogRead(uint8_t pin)
{
if(!__adcAttachPin(pin) || !__adcStart(pin)){
return 0;
}
return __adcEnd(pin);
}

void __analogReadResolution(uint8_t bits)
{
if(!bits || bits > 16){
return;
}
__analogSetWidth(bits); // hadware from 9 to 12
__analogReturnedWidth = bits; // software from 1 to 16
}

int __hallRead() //hall sensor without LNA
Expand Down Expand Up @@ -192,10 +258,16 @@ int __hallRead() //hall sensor without LNA
}

extern uint16_t analogRead(uint8_t pin) __attribute__ ((weak, alias("__analogRead")));
extern void analogReadResolution(uint8_t bits) __attribute__ ((weak, alias("__analogReadResolution")));
extern void analogSetWidth(uint8_t bits) __attribute__ ((weak, alias("__analogSetWidth")));
extern void analogSetCycles(uint8_t cycles) __attribute__ ((weak, alias("__analogSetCycles")));
extern void analogSetSamples(uint8_t samples) __attribute__ ((weak, alias("__analogSetSamples")));
extern void analogSetClockDiv(uint8_t clockDiv) __attribute__ ((weak, alias("__analogSetClockDiv")));
extern void analogSetAttenuation(adc_attenuation_t attenuation) __attribute__ ((weak, alias("__analogSetAttenuation")));
extern void analogSetPinAttenuation(uint8_t pin, adc_attenuation_t attenuation) __attribute__ ((weak, alias("__analogSetPinAttenuation")));
extern int hallRead() __attribute__ ((weak, alias("__hallRead")));

extern bool adcAttachPin(uint8_t pin) __attribute__ ((weak, alias("__adcAttachPin")));
extern bool adcStart(uint8_t pin) __attribute__ ((weak, alias("__adcStart")));
extern bool adcBusy(uint8_t pin) __attribute__ ((weak, alias("__adcBusy")));
extern uint16_t adcEnd(uint8_t pin) __attribute__ ((weak, alias("__adcEnd")));
40 changes: 39 additions & 1 deletion cores/esp32/esp32-hal-adc.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,16 @@ typedef enum {
uint16_t analogRead(uint8_t pin);

/*
* Sets the sample bits
* Set the resolution of analogRead return values. Default is 12 bits (range from 0 to 4096).
* If between 9 and 12, it will equal the set hardware resolution, else value will be shifted.
* Range is 1 - 16
*
* Note: compatibility with Arduino SAM
*/
void analogReadResolution(uint8_t bits);

/*
* Sets the sample bits and read resolution
* Default is 12bit (0 - 4095)
* Range is 9 - 12
* */
Expand Down Expand Up @@ -88,6 +97,35 @@ void analogSetPinAttenuation(uint8_t pin, adc_attenuation_t attenuation);
* */
int hallRead();

/*
* Non-Blocking API (almost)
*
* Note: ADC conversion can run only for single pin at a time.
* That means that if you want to run ADC on two pins on the same bus,
* you need to run them one after another. Probably the best use would be
* to start conversion on both buses in parallel.
* */

/*
* Attach pin to ADC (will also clear any other analog mode that could be on)
* */
bool adcAttachPin(uint8_t pin);

/*
* Start ADC conversion on attached pin's bus
* */
bool adcStart(uint8_t pin);

/*
* Check if conversion on the pin's ADC bus is currently running
* */
bool adcBusy(uint8_t pin);

/*
* Get the result of the conversion (will wait if it have not finished)
* */
uint16_t adcEnd(uint8_t pin);

#ifdef __cplusplus
}
#endif
Expand Down

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