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Stm32l47x adc temperature #265

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Merged
merged 1 commit into from
Dec 13, 2021
Merged

Stm32l47x adc temperature #265

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11 changes: 7 additions & 4 deletions src/adc.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@ use crate::{
},
pac,
rcc::{Enable, Reset, AHB2, CCIPR},
signature::{VrefCal, VtempCal130, VtempCal30, VDDA_CALIB_MV},
signature::{VrefCal, VtempCalHigh, VtempCalLow, VDDA_CALIB_MV},
};

use pac::{ADC1, ADC_COMMON};
Expand Down Expand Up @@ -201,6 +201,7 @@ impl ADC {
pub fn enable_temperature(&mut self, delay: &mut impl DelayUs<u32>) -> Temperature {
self.common.ccr.modify(|_, w| w.ch17sel().set_bit());

// FIXME: This note from the reference manual is currently not possible
// rm0351 section 18.4.32 pg580 (L47/L48/L49/L4A models)
// Note:
// The sensor has a startup time after waking from power-down mode before it can output VTS
Expand Down Expand Up @@ -278,12 +279,14 @@ impl ADC {
/// Convert a raw sample from the `Temperature` to deg C
pub fn to_degrees_centigrade(&self, sample: u16) -> f32 {
let sample = (u32::from(sample) * self.calibrated_vdda) / VDDA_CALIB_MV;
(VtempCal130::TEMP_DEGREES - VtempCal30::TEMP_DEGREES) as f32
(VtempCalHigh::TEMP_DEGREES - VtempCalLow::TEMP_DEGREES) as f32
// as signed because RM0351 doesn't specify against this being an
// inverse relation (which would result in a negative differential)
/ (VtempCal130::get().read() as i32 - VtempCal30::get().read() as i32) as f32
/ (VtempCalHigh::get().read() as i32 - VtempCalLow::get().read() as i32) as f32
// this can definitely be negative so must be done as a signed value
* (sample as i32 - VtempCal30::get().read() as i32) as f32
* (sample as i32 - VtempCalLow::get().read() as i32) as f32
// while it would make sense for this to be `VtempCalLow::TEMP_DEGREES` (which is 30*C),
// the RM specifically uses 30*C so this will too
+ 30.0
}

Expand Down
28 changes: 22 additions & 6 deletions src/signature.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -96,10 +96,10 @@ impl VrefCal {
/// aka TS_CAL1 in reference manual
#[derive(Debug)]
#[repr(C)]
pub struct VtempCal30(u16);
define_ptr_type!(VtempCal30, 0x1FFF_75A8);
pub struct VtempCalLow(u16);
define_ptr_type!(VtempCalLow, 0x1FFF_75A8);

impl VtempCal30 {
impl VtempCalLow {
/// aka TS_CAL1_TEMP in reference manual
pub const TEMP_DEGREES: u16 = 30;
/// Read calibration value
Expand All @@ -112,13 +112,29 @@ impl VtempCal30 {
/// aka TS_CAL2 in reference manual
#[derive(Debug)]
#[repr(C)]
pub struct VtempCal130(u16);
define_ptr_type!(VtempCal130, 0x1FFF_75CA);
pub struct VtempCalHigh(u16);
define_ptr_type!(VtempCalHigh, 0x1FFF_75CA);

impl VtempCal130 {
impl VtempCalHigh {
/// aka TS_CAL2_TEMP in reference manual
/// Feature gate Required: this is 110 for L47x/L48x, 130 for other L4s according to
/// https://github.com/STMicroelectronics/STM32CubeL4/blob/5e1553e07706491bd11f4edd304e093b6e4b83a4/Drivers/STM32L4xx_HAL_Driver/Inc/stm32l4xx_ll_adc.h#L352-L356

// L47/L48
#[cfg(any(
feature = "stm32l471",
feature = "stm32l475",
feature = "stm32l476",
feature = "stm32l486"
))]
pub const TEMP_DEGREES: u16 = 110;
// else
#[cfg(not(any(
feature = "stm32l471",
feature = "stm32l475",
feature = "stm32l476",
feature = "stm32l486"
)))]
pub const TEMP_DEGREES: u16 = 130;
/// Read calibration value
pub fn read(&self) -> u16 {
Expand Down