alema/usbc_soldering_iron
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changed _k to _c to reflect reality, tip temperature approx

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Alessandro Mauri 2026-04-28 19:34:20 +02:00
parent 4ffb554d43
commit 7cf89e9e45
1 changed files with 15 additions and 9 deletions
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24
fw/main.c
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@ -34,7 +34,7 @@
#define PWM_FREQ_HZ 150000
// constants
// LUT for converting NTC readings to degrees kelvin
// LUT for converting NTC readings to degrees celsius
// Nominal: 1kOhm, Beta: 3380, Step: 64
const uint8_t ntc_step_size = 64;
const int16_t ntc_lut[] = {
@ -51,10 +51,15 @@ int16_t encoder = 0; // rotary encoder counter
uint32_t last_interrupt = 0; // last time the encoder interrupt was triggered
#define ENCODER_DEBOUNCE 6000
// TODO: these need to be calibrated
// Tip mV to deg C conversion factor numerator
#define TC_CONV_NOM 151
// Tip mV to deg C conversion factor denumerator
#define TC_CONV_DEN 1000
// Convert the raw adc reading to a temperature in kelvin with the ntc lut,
// Convert the raw adc reading to a temperature in celsius with the ntc lut,
// linearly interpolating between positions
static inline int16_t get_temp_k(uint16_t adc_reading)
static inline int16_t get_temp_c(uint16_t adc_reading)
{
if (adc_reading > 4095) return 0;
uint8_t index = adc_reading / ntc_step_size;
@ -465,19 +470,20 @@ __attribute__((noreturn)) int main(void)
}
for (;;) {
static uint16_t tip_mv, vbus_mv, current_ma;
static int16_t temp_k;
static uint16_t vbus_mv, current_ma;
static int16_t temp_c, tip_temp_c;
u32 start = funSysTick32();
poll_input(); // usb
vbus_mv = U16_FP_EMA_K4(vbus_mv, ((u32)adc_buffer[0]*VCC_MV*11)/4096);
current_ma = U16_FP_EMA_K4(current_ma, get_current_ma(adc_buffer[1]));
temp_k = I16_FP_EMA_K4(temp_k, get_temp_k(adc_buffer[2]));
temp_c = I16_FP_EMA_K4(temp_c, get_temp_c(adc_buffer[2]));
if (!adc_injection_conversion()) {
printf("injection conversion failed");
} else {
tip_mv = U16_FP_EMA_K4(tip_mv, (u32)(injection_results[0]*VCC_MV)/4096);
u32 tip_mv = ((u32)injection_results[0]*VCC_MV)/4096;
tip_temp_c = I16_FP_EMA_K2(tip_temp_c, (tip_mv*TC_CONV_NOM)/TC_CONV_DEN) + temp_c;
}
static bool pwm = false;
@ -503,11 +509,11 @@ __attribute__((noreturn)) int main(void)
static bool mode = true;
// if (mode) {
u8g2_DrawStr(u8g2, x_off+0, y_off+7, "TIP:");
u8g2_DrawStr(u8g2, x_off+20, y_off+7, u8x8_u16toa(tip_mv, 4));
u8g2_DrawStr(u8g2, x_off+20, y_off+7, u8x8_u16toa(tip_temp_c, 4));
u8g2_DrawStr(u8g2, x_off+0, y_off+15, "VBUS:");
u8g2_DrawStr(u8g2, x_off+25, y_off+15, u8x8_u16toa(vbus_mv, 4));
u8g2_DrawStr(u8g2, x_off+51, y_off+7, "TEMP:");
u8g2_DrawStr(u8g2, x_off+75, y_off+7, u8x8_u16toa(temp_k, 2));
u8g2_DrawStr(u8g2, x_off+75, y_off+7, u8x8_u16toa(temp_c, 2));
//u8g2_DrawStr(u8g2, x_off+51, y_off+15, "V:");
//u8g2_DrawStr(u8g2, x_off+60, y_off+15, u8x8_u16toa(max_v, 2));
u8g2_DrawStr(u8g2, x_off+50, y_off+15, "CURR:");