djsundog/circuitpython
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add ADC support for internal TEMP/VBAT/VREF

Browse Source 
* Add ADC support for reading internal temperature sensor.
* Add ADC support for reading internal VREF/VBAT monitor.
This commit is contained in:
mux 2014-01-14 22:32:53 +02:00
parent 3591285091
commit 8c10240722
1 changed files with 143 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

145
stm/adc.c
View File

@ -13,6 +13,28 @@
#define ADCx_CLK (RCC_APB2Periph_ADC1)
#define ADC_NUM_CHANNELS (16)
/* Internally connected ADC channels Temp/VBAT/VREF*/
#if defined (STM32F40XX) || defined(STM32F41XX)
#define ADC_TEMP_CHANNEL (16)
#define ADC_VBAT_CHANNEL (18)
#define ADC_VREF_CHANNEL (17)
#elif defined (STM32F42XX) || defined(STM32F43XX)
#define ADC_TEMP_CHANNEL (18)
#define ADC_VBAT_CHANNEL (18) /* same channel as TEMP */
#define ADC_VREF_CHANNEL (17)
#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) */
/* VBAT divider */
#if defined (STM32F40XX) || defined(STM32F41XX)
#define VBAT_DIV (2)
#elif defined (STM32F42XX) || defined(STM32F43XX)
#define VBAT_DIV (4)
#endif
/* GPIO struct */
typedef struct {
GPIO_TypeDef* port;
@ -82,6 +104,12 @@ void adc_init(uint32_t resolution) {
/* Enable ADCx */
ADC_Cmd(ADCx, ENABLE);
/* Enable VBAT/VREF monitor */
ADC_VBATCmd(ENABLE);
/* Enable temperature sensor */
ADC_TempSensorVrefintCmd(ENABLE);
}
uint32_t adc_read_channel(int channel)
@ -93,7 +121,7 @@ uint32_t adc_read_channel(int channel)
}
/* ADC regular channel config ADC/Channel/SEQ Rank/Sample time */
ADC_RegularChannelConfig(ADCx, channel, 1, ADC_SampleTime_3Cycles);
ADC_RegularChannelConfig(ADCx, channel, 1, ADC_SampleTime_15Cycles);
/* Start ADC single conversion */
ADC_SoftwareStartConv(ADCx);
@ -102,7 +130,7 @@ uint32_t adc_read_channel(int channel)
while(!ADC_GetFlagStatus(ADCx, ADC_FLAG_EOC) && --timeout >0) {
}
/* ADC conversion timed out */
/* ADC conversion timed out */
if (timeout == 0) {
return 0;
}
@ -111,6 +139,80 @@ uint32_t adc_read_channel(int channel)
return ADC_GetConversionValue(ADCx);
}
int adc_read_core_temp()
{
int timeout = 10000;
/* ADC temperature sensor channel config ADC/Channel/SEQ Rank/Sample time */
/* Note: sample time must be higher than minimum sample time */
ADC_RegularChannelConfig(ADCx, ADC_TEMP_CHANNEL, 1, ADC_SampleTime_480Cycles);
/* Start ADC single conversion */
ADC_SoftwareStartConv(ADCx);
/* Wait for conversion to be complete*/
while(!ADC_GetFlagStatus(ADCx, ADC_FLAG_EOC) && --timeout >0) {
}
/* ADC conversion timed out */
if (timeout == 0) {
return 0;
}
/* Convert ADC reading to temperature */
/* Temperature formula from datasheet P.411 */
return ((ADC_GetConversionValue(ADCx) - CORE_TEMP_V25) / CORE_TEMP_AVG_SLOPE) + 25;
}
float adc_read_core_vbat()
{
int timeout = 10000;
/* ADC VBAT channel config ADC/Channel/SEQ Rank/Sample time */
/* Note: sample time must be higher than minimum sample time */
ADC_RegularChannelConfig(ADCx, ADC_VBAT_CHANNEL, 1, ADC_SampleTime_144Cycles);
/* Start ADC single conversion */
ADC_SoftwareStartConv(ADCx);
/* Wait for conversion to be complete */
while(!ADC_GetFlagStatus(ADCx, ADC_FLAG_EOC) && --timeout >0) {
}
/* ADC conversion timed out */
if (timeout == 0) {
return 0;
}
/* Convert ADC reading to voltage, VBAT pin is
internally connected to a bridge divider by VBAT_DIV */
return ADC_GetConversionValue(ADCx)*VBAT_DIV/4096.0f*3.3f;
}
float adc_read_core_vref()
{
int timeout = 10000;
/* ADC VBAT channel config ADC/Channel/SEQ Rank/Sample time */
/* Note: sample time must be higher than minimum sample time */
ADC_RegularChannelConfig(ADCx, ADC_VREF_CHANNEL, 1, ADC_SampleTime_112Cycles);
/* Start ADC single conversion */
ADC_SoftwareStartConv(ADCx);
/* Wait for conversion to be complete*/
while(!ADC_GetFlagStatus(ADCx, ADC_FLAG_EOC) && --timeout >0) {
}
/* ADC conversion timed out */
if (timeout == 0) {
return 0;
}
/* Convert ADC reading to voltage */
return ADC_GetConversionValue(ADCx)/4096.0f*3.3f;
}
/******************************************************************************/
/* Micro Python bindings */
@ -132,15 +234,54 @@ static mp_obj_t adc_obj_read_channel(mp_obj_t self_in, mp_obj_t channel) {
return ret;
}
static mp_obj_t adc_obj_read_core_temp(mp_obj_t self_in) {
mp_obj_t ret = mp_const_none;
pyb_adc_obj_t *self = self_in;
if (self->is_enabled) {
int data = adc_read_core_temp();
ret = mp_obj_new_int(data);
}
return ret;
}
static mp_obj_t adc_obj_read_core_vbat(mp_obj_t self_in) {
mp_obj_t ret = mp_const_none;
pyb_adc_obj_t *self = self_in;
if (self->is_enabled) {
float data = adc_read_core_vbat();
ret = mp_obj_new_float(data);
}
return ret;
}
static mp_obj_t adc_obj_read_core_vref(mp_obj_t self_in) {
mp_obj_t ret = mp_const_none;
pyb_adc_obj_t *self = self_in;
if (self->is_enabled) {
float data = adc_read_core_vref();
ret = mp_obj_new_float(data);
}
return ret;
}
static void adc_obj_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in) {
pyb_adc_obj_t *self = self_in;
print(env, "<ADC %lu>", self->adc_id);
}
static MP_DEFINE_CONST_FUN_OBJ_2(adc_obj_read_channel_obj, adc_obj_read_channel);
static MP_DEFINE_CONST_FUN_OBJ_1(adc_obj_read_core_temp_obj, adc_obj_read_core_temp);
static MP_DEFINE_CONST_FUN_OBJ_1(adc_obj_read_core_vbat_obj, adc_obj_read_core_vbat);
static MP_DEFINE_CONST_FUN_OBJ_1(adc_obj_read_core_vref_obj, adc_obj_read_core_vref);
static const mp_method_t adc_methods[] = {
{ "read_channel", &adc_obj_read_channel_obj},
{ "read_core_temp", &adc_obj_read_core_temp_obj},
{ "read_core_vbat", &adc_obj_read_core_vbat_obj},
{ "read_core_vref", &adc_obj_read_core_vref_obj},
{ NULL, NULL },
};