From: asterix <asterix@38d2e660-2303-0410-9eaa-f027e97ec537>
Date: Wed, 11 Jan 2012 14:40:10 +0000 (+0000)
Subject: Fix a bug when reading negative temperatures.
X-Git-Url: https://codewiz.org/gitweb?a=commitdiff_plain;h=e957b9c1c7935ab27d2b7f96fded1914f303ddec;p=bertos.git

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 d1d0a257..fd442024 100644
--- 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;
 }