Merge branch 'feature/protocol-use-transit-u26' into feature/base-type-error-correcting

lib-bms-protocol/src/lib.rs

@@ -8,6 +8,8 @@ mod types;
 use embedded_hal::i2c::{I2c, Operation, SevenBitAddress};
 use thiserror::Error;
 
+use crate::types::Transit_U26;
+
 pub const BMS_I2C_ADDRESS: u8 = 0x55;
 
 pub trait BmsReadable {
@@ -27,6 +29,8 @@ pub trait BmsWriteable {
 pub enum BmsProtocolError {
     #[error("i2c communication failed")]
     I2cCommunicationError,
+    #[error("checksum error in received data")]
+    ChecksumError,
 }
 
 impl<E> From<E> for BmsProtocolError
@@ -38,6 +42,15 @@ where
     }
 }
 
+impl From<crate::types::U26Error> for BmsProtocolError {
+    fn from(error: crate::types::U26Error) -> Self {
+        match error {
+            crate::types::U26Error::ChecksumError => Self::ChecksumError,
+            _ => Self::I2cCommunicationError,
+        }
+    }
+}
+
 #[derive(Debug)]
 pub struct BmsSoftwareReset;
 
@@ -73,7 +86,8 @@ impl BmsReadable for ProtocolVersion {
                 Operation::Read(&mut version),
             ],
         )?;
-        Ok(ProtocolVersion(u32::from_be_bytes(version)))
+        let transit = Transit_U26::from_be_bytes(version)?;
+        Ok(ProtocolVersion(transit.into()))
     }
 }
 
@@ -96,7 +110,8 @@ impl BmsReadable for FirmwareVersion {
                 Operation::Read(&mut version),
             ],
         )?;
-        Ok(FirmwareVersion(u32::from_be_bytes(version)))
+        let transit = Transit_U26::from_be_bytes(version)?;
+        Ok(FirmwareVersion(transit.into()))
     }
 }
 
@@ -127,9 +142,9 @@ impl BmsReadable for Config {
             ],
         )?;
         Ok(Config {
-            capacity_mah: u32::from_be_bytes(capacity_mah),
+            capacity_mah: Transit_U26::from_be_bytes(capacity_mah)?.into(),
-            v_full_mv: u32::from_be_bytes(v_full_mv),
+            v_full_mv: Transit_U26::from_be_bytes(v_full_mv)?.into(),
-            v_empty_mv: u32::from_be_bytes(v_empty_mv),
+            v_empty_mv: Transit_U26::from_be_bytes(v_empty_mv)?.into(),
         })
     }
 }
@@ -167,11 +182,12 @@ impl BmsReadable for BatteryState {
             ],
         )?;
         Ok(BatteryState {
-            lifetime_capacity_mah: u32::from_be_bytes(lifetime_capacity_mah),
+            lifetime_capacity_mah: Transit_U26::from_be_bytes(lifetime_capacity_mah)?.into(),
-            remaining_capacity_mah: u32::from_be_bytes(remaining_capacity_mah),
+            remaining_capacity_mah: Transit_U26::from_be_bytes(remaining_capacity_mah)?.into(),
-            current_mv: u32::from_be_bytes(current_mv),
+            current_mv: Transit_U26::from_be_bytes(current_mv)?.into(),
-            temperature_celcius: i32::from_be_bytes(temperature_celcius),
+            temperature_celcius: crate::types::Transit_I26::from_be_bytes(temperature_celcius)?
-            health_percent: u32::from_be_bytes(health_percent),
+                .into(),
+            health_percent: Transit_U26::from_be_bytes(health_percent)?.into(),
         })
     }
 }
@@ -194,9 +210,9 @@ impl BmsReadable for ChargeInfoWindowSec {
                 Operation::Read(&mut charge_info_window_sec),
             ],
         )?;
-        Ok(ChargeInfoWindowSec(u32::from_be_bytes(
+        Ok(ChargeInfoWindowSec(
-            charge_info_window_sec,
+            Transit_U26::from_be_bytes(charge_info_window_sec)?.into(),
-        )))
+        ))
     }
 }
 
@@ -206,11 +222,12 @@ impl BmsWriteable for ChargeInfoWindowSec {
         I: I2c<SevenBitAddress>,
     {
         let cmd = BmsRegisterMap::ChargoInfoWindowTotalSecs;
+        let transit = Transit_U26::try_from(self.0)?;
         i2c_dev.transaction(
             BMS_I2C_ADDRESS,
             &mut [
                 Operation::Write(&(cmd as u32).to_be_bytes()),
-                Operation::Write(&self.0.to_be_bytes()),
+                Operation::Write(&transit.to_be_bytes()),
             ],
         )?;
         Ok(())
@@ -250,11 +267,11 @@ impl BmsReadable for ChargeInfo {
             ],
         )?;
         Ok(ChargeInfo {
-            total_charge_ma: u32::from_be_bytes(total_charge_ma),
+            total_charge_ma: Transit_U26::from_be_bytes(total_charge_ma)?.into(),
-            total_discharge_ma: u32::from_be_bytes(total_discharge_ma),
+            total_discharge_ma: Transit_U26::from_be_bytes(total_discharge_ma)?.into(),
-            max_charge_mw: u32::from_be_bytes(max_charge_mw),
+            max_charge_mw: Transit_U26::from_be_bytes(max_charge_mw)?.into(),
-            max_discharge_mw: u32::from_be_bytes(max_discharge_mw),
+            max_discharge_mw: Transit_U26::from_be_bytes(max_discharge_mw)?.into(),
-            avg_voltage_mv: u32::from_be_bytes(avg_voltage_mv),
+            avg_voltage_mv: Transit_U26::from_be_bytes(avg_voltage_mv)?.into(),
         })
     }
 }

lib-bms-protocol/src/types.rs

@@ -165,7 +165,7 @@ impl Transit_U26 {
 
 impl From<Transit_U26> for u32 {
     fn from(value: Transit_U26) -> Self {
-        value.0 & U26_VALUE_MASK >> 6
+        (value.0 & U26_VALUE_MASK) >> 6
     }
 }
 
@@ -181,6 +181,58 @@ impl TryFrom<u32> for Transit_U26 {
     }
 }
 
+#[derive(Debug, PartialEq)]
+/// this type is used for transmitting signed 26-bit integer data
+/// It wraps the Transit_U26 type to provide i32 support
+/// The i32 value is converted to u32 by casting, preserving the bit pattern
+/// This ensures proper sign extension when converting between signed and unsigned
+/// Valid range: -33554432 to 33554431 (26-bit signed)
+pub struct Transit_I26(Transit_U26);
+
+impl Transit_I26 {
+    pub fn new(value: i32) -> Result<Self, U26Error> {
+        // Check if value is within 26-bit signed range
+        if value < -0x02000000 || value > 0x01FFFFFF {
+            return Err(U26Error::Overflow);
+        }
+        // Extract only the lower 26 bits
+        let u26_val = (value as u32) & 0x03FFFFFF;
+        let transit_u26 = Transit_U26::try_from(u26_val)?;
+        Ok(Self(transit_u26))
+    }
+
+    pub fn from_be_bytes(bytes: [u8; 4]) -> Result<Self, U26Error> {
+        let transit_u26 = Transit_U26::from_be_bytes(bytes)?;
+        Ok(Self(transit_u26))
+    }
+
+    pub fn to_be_bytes(&self) -> [u8; 4] {
+        self.0.to_be_bytes()
+    }
+}
+
+impl From<Transit_I26> for i32 {
+    fn from(value: Transit_I26) -> Self {
+        // Convert u32 back to i32 by casting, preserving the exact bit pattern
+        let u32_val: u32 = value.0.into();
+        // Interpret as signed 26-bit integer
+        if u32_val & 0x02000000 != 0 {
+            // Sign-extend to 32 bits
+            (u32_val as i32) | 0xFC000000u32 as i32
+        } else {
+            u32_val as i32
+        }
+    }
+}
+
+impl TryFrom<i32> for Transit_I26 {
+    type Error = U26Error;
+
+    fn try_from(value: i32) -> Result<Self, Self::Error> {
+        Self::new(value)
+    }
+}
+
 // only calc hemming code for the first 24 data bits including the 5 hemming bits
 //  pos  |     | p1  | p2  | p3  | p4  | p5  |
 // 00001 | p1  |  o  |     |     |     |     |
@@ -358,9 +410,9 @@ pub fn check_hemming(data: u32, hemming: u8) -> Result<(), HemmingCorrectionValu
 /// - All double-bit errors
 /// - Random errors with a probability of 2^-6 = 0.015625 of going undetected
 pub fn calc_crc6(data: u32) -> u8 {
-    let mut crc: u8 = 0x00; 
+    let mut crc: u8 = 0x00;
     for pos in 0..32 {
-        if ((data >> (31-pos)) & 0x1) ^ ((crc >> 5) & 0x1) as u32 != 0 {
+        if ((data >> (31 - pos)) & 0x1) ^ ((crc >> 5) & 0x1) as u32 != 0 {
             crc = ((crc << 1) ^ 0x03) & 0x3F;
         } else {
             crc = (crc << 1) & 0x3F;
@@ -374,9 +426,9 @@ pub fn calc_crc6(data: u32) -> u8 {
 /// This function is the mirror piece to the crc6 calculation, it checks a crc value against
 /// the data to determine if the crc is valid.
 pub fn check_crc6(data: u32, crc: u8) -> bool {
-    let mut check_crc: u8 = 0x00; 
+    let mut check_crc: u8 = 0x00;
     for pos in 0..32 {
-        if ((data >> (31-pos)) & 0x1) ^ ((check_crc >> 5) & 0x1) as u32 != 0 {
+        if ((data >> (31 - pos)) & 0x1) ^ ((check_crc >> 5) & 0x1) as u32 != 0 {
             check_crc = ((check_crc << 1) ^ 0x03) & 0x3F;
         } else {
             check_crc = (check_crc << 1) & 0x3F;
@@ -388,7 +440,8 @@ pub fn check_crc6(data: u32, crc: u8) -> bool {
 #[cfg(test)]
 mod base_type_tests {
     use super::{
-        Stored_U26, Transit_U26, U26_MAX_VALUE, calc_crc6, calc_hemming, check_crc6, check_hemming,
+        calc_crc6, calc_hemming, check_crc6, check_hemming, Stored_U26, Transit_I26, Transit_U26,
+        U26_MAX_VALUE,
     };
     use crate::types::U26Error;
 
@@ -515,4 +568,52 @@ mod base_type_tests {
             assert!(!check_crc6(corrupted_data, original_crc));
         }
     }
+
+    #[test]
+    fn transit_i26_positive_values() {
+        let data = Transit_I26::new(12345).unwrap();
+        let bytes = data.to_be_bytes();
+        let decoded = Transit_I26::from_be_bytes(bytes).unwrap();
+        assert_eq!(i32::from(decoded), 12345);
+    }
+
+    #[test]
+    fn transit_i26_negative_values() {
+        let data = Transit_I26::new(-12345).unwrap();
+        let bytes = data.to_be_bytes();
+        let decoded = Transit_I26::from_be_bytes(bytes).unwrap();
+        assert_eq!(i32::from(decoded), -12345);
+    }
+
+    #[test]
+    fn transit_i26_zero() {
+        let data = Transit_I26::new(0).unwrap();
+        let bytes = data.to_be_bytes();
+        let decoded = Transit_I26::from_be_bytes(bytes).unwrap();
+        assert_eq!(i32::from(decoded), 0);
+    }
+
+    #[test]
+    fn transit_i26_max_positive() {
+        let data = Transit_I26::new(0x01FFFFFF).unwrap();
+        let bytes = data.to_be_bytes();
+        let decoded = Transit_I26::from_be_bytes(bytes).unwrap();
+        assert_eq!(i32::from(decoded), 0x01FFFFFF as i32);
+    }
+
+    #[test]
+    fn transit_i26_max_negative() {
+        let data = Transit_I26::new(-0x01FFFFFF).unwrap();
+        let bytes = data.to_be_bytes();
+        let decoded = Transit_I26::from_be_bytes(bytes).unwrap();
+        assert_eq!(i32::from(decoded), -0x01FFFFFF as i32);
+    }
+
+    #[test]
+    fn transit_i26_checksum_error() {
+        let data = Transit_I26::new(12345).unwrap();
+        let mut bytes = data.to_be_bytes();
+        bytes[1] ^= 0x01; // Corrupt one byte
+        assert!(Transit_I26::from_be_bytes(bytes).is_err());
+    }
 }