jaseg/7seg
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

ADC temperature measurement works now

Browse source
This commit is contained in:
jaseg 2017-12-10 13:28:23 +01:00
parent 322b306bf2
commit 3ec035844f
1 changed files with 12 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

20
fw/main.c
View file

@ -89,7 +89,7 @@ void strobe_leds(void) {
#define VREFINT_CAL (*(uint16_t *)0x1FFFF7BA)
volatile int16_t adc_vcc_mv = 0;
volatile int16_t adc_temp_tenth_celsius = 0;
volatile int16_t adc_temp_celsius = 0;
volatile uint16_t adc_buf[2];
@ -541,7 +541,7 @@ void USART1_IRQHandler(void) {
}
}
#define ADC_OVERSAMPLING 4
#define ADC_OVERSAMPLING 8
uint32_t vsense;
void DMA1_Channel1_IRQHandler(void) {
/* This interrupt takes either 1.2us or 13us. It can be pre-empted by the more timing-critical UART and LED timer
@ -556,13 +556,17 @@ void DMA1_Channel1_IRQHandler(void) {
adc_aggregate[0] += adc_buf[0];
adc_aggregate[1] += adc_buf[1];
if (count++ == (1<<ADC_OVERSAMPLING)) {
/* This has been cobbled together from online tutorials and ST documentation. The datasheet is pretty poor on
* this. */
if (++count == (1<<ADC_OVERSAMPLING)) {
/* This has been copied from the code examples to section 12.9 ADC>"Temperature sensor and internal reference
* voltage" in the reference manual with the extension that we actually measure the supply voltage instead of
* hardcoding it. This is not strictly necessary since we're running off a bored little LDO but it's free and
* the current supply voltage is a nice health value.
*/
adc_vcc_mv = (3300 * VREFINT_CAL)/(adc_aggregate[0]>>ADC_OVERSAMPLING);
vsense = ((adc_aggregate[1]>>ADC_OVERSAMPLING) * adc_vcc_mv)/4095 ;
adc_temp_tenth_celsius = 300 - (((TS_CAL1*adc_vcc_mv/4095) - vsense)*100)/43;
/* Reset oversampling state */
int32_t temperature = (((uint32_t)TS_CAL1) - ((adc_aggregate[1]>>ADC_OVERSAMPLING) * adc_vcc_mv / 3300)) * 1000;
temperature = (temperature/5336) + 30;
adc_temp_celsius = temperature;
count = 0;
adc_aggregate[0] = 0;
adc_aggregate[1] = 0;