Fix a bug when reading negative temperatures.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@5235 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/bertos/drv/lm75.c b/bertos/drv/lm75.c
index d1d0a257fc2f7e6b0b582ac44da716ffc0e0485e..fd44202492b2c0fe67ae1a2091a0eb26d3a23c0c 100644 (file)
--- a/bertos/drv/lm75.c
+++ b/bertos/drv/lm75.c
@@ -74,7 +74,6 @@ deg_t lm75_read_1(uint8_t sens_addr)
 deg_t lm75_read_2(I2c *i2c, uint8_t sens_addr)
 {
        uint8_t data[2];
-       int16_t degree;
        int16_t deci_degree;
 
        i2c_start_w(i2c, SELECT_ADDRESS(sens_addr), 1, I2C_NOSTOP);
@@ -85,10 +84,11 @@ deg_t lm75_read_2(I2c *i2c, uint8_t sens_addr)
        if (i2c_error(i2c))
                return EOF;
 
-       degree = (int16_t)data[0];
-       deci_degree = (int16_t)(((data[1] >> 7) & 1 ) * 5);
+       deci_degree = ((data[0] << 8) | data[1]);
+       deci_degree >>= 7;
+       deci_degree *= 5;
 
-       LOG_INFO("[%d.%d C]\n", degree, deci_degree);
+       LOG_INFO("[%d.%d C]\n", deci_degree / 10, ABS(deci_degree % 10));
 
-       return degree * 10 + deci_degree;
+       return deci_degree;
 }