Atomic HRS reads (#1845)

- Combine the reading of all `HRS3300` registers into one I2C read so data is not partial
- Downsizes both HRS and ALS to 16bit as the sensor does not generate larger than
  16bit values in its current configuration
  - Increasing the resolution by 1 bit doubles the sensor acquisition time,
    since we are already at 10Hz we are never going to use a higher resolution
  - The PPG algorithm buffers for ALS/HRS are already 16bit anyway
- Remove functions for setting gain / drive that are unused throughout the codebase
- Calculate constants with constexpr

2 files changed, 2 insertions, 2 deletions

diff --git a/src/components/heartrate/Ppg.cpp b/src/components/heartrate/Ppg.cpp
index 3a6988ae..efbed852 100644
--- a/src/components/heartrate/Ppg.cpp
+++ b/src/components/heartrate/Ppg.cpp
@@ -142,7 +142,7 @@ Ppg::Ppg() {
   spectrum.fill(0.0f);
 }
 
-int8_t Ppg::Preprocess(uint32_t hrs, uint32_t als) {
+int8_t Ppg::Preprocess(uint16_t hrs, uint16_t als) {
   if (dataIndex < dataLength) {
     dataHRS[dataIndex++] = hrs;
   }
diff --git a/src/components/heartrate/Ppg.h b/src/components/heartrate/Ppg.h
index 4492b2c2..373e7985 100644
--- a/src/components/heartrate/Ppg.h
+++ b/src/components/heartrate/Ppg.h
@@ -14,7 +14,7 @@ namespace Pinetime {
     class Ppg {
     public:
       Ppg();
-      int8_t Preprocess(uint32_t hrs, uint32_t als);
+      int8_t Preprocess(uint16_t hrs, uint16_t als);
       int HeartRate();
       void Reset(bool resetDaqBuffer);
       static constexpr int deltaTms = 100;