Revision 3:beca2e65b1b0, committed 2017-10-14

Comitter:

sm168j

Date:

Sat Oct 14 20:10:05 2017 -0500

Parent:

2:d85076c18c80

Commit message:

Corrected temperature reading calculation

Changed in this revision

--- a/SI7210.h	Thu Sep 14 00:09:07 2017 +0000
+++ b/SI7210.h	Sat Oct 14 20:10:05 2017 -0500
@@ -34,7 +34,7 @@
  *     ok = si7210.enable() &&
  *          si7210.read(&data) &&
  *          si7210.disable();
- *           
+ *
  *     if (ok) {
             printf("Mag T: %f\r\n", data.mag_T);
             printf("temp C/F: %f/%f\r\n", data.temp_C, data.temp_C * 9 / 5 + 32);
@@ -140,7 +140,7 @@
     bool read(si7210_measurements_t * data) {
         uint16_t    magRaw;
         uint16_t    tempRaw;
-        
+
         bool ok = _write_reg(SI72XX_ARAUTOINC, ARAUTOINC__ARAUTOINC_MASK)
                && _write_reg(SI72XX_DSPSIGSEL, DSPSIGSEL__MAG_VAL_SEL)      //capture mag field measurement
                && _write_reg(SI72XX_POWER_CTRL, POWER_CTRL__ONEBURST_MASK)
@@ -150,9 +150,9 @@
                && _read_regs(SI72XX_DSPSIGM, 2, &tempRaw);
 
         if (ok && !_isTempOffsetAndGainValid) {
-            char otpTempOffset;
-            char otpTempGain;
-            
+            signed char otpTempOffset;
+            signed char otpTempGain;
+
             ok = _read_otp(SI72XX_OTP_TEMP_OFFSET, &otpTempOffset)
               && _read_otp(SI72XX_OTP_TEMP_GAIN, &otpTempGain);
             if (ok) {
@@ -161,7 +161,7 @@
                 _isTempOffsetAndGainValid = true;
             }
         }
-        
+
         if (ok) {
             magRaw = ((magRaw >> 8) & 0xff) + ((magRaw & 0xff) << 8);
             tempRaw = ((tempRaw >> 8) & 0xff) + ((tempRaw & 0xff) << 8);
@@ -170,7 +170,7 @@
             data->temp_C = (float)((tempRaw & ~0x8000) >> 3);
             data->temp_C = _tempGain * (-3.83e-6F * data->temp_C * data->temp_C + 0.16094F * data->temp_C - 279.80F - 0.222F * 3.0F) + _tempOffset;
         }
-        
+
         return ok;
     }
 
@@ -189,11 +189,11 @@
     bool _i2c_transfer(int address, void * buff, size_t writeSize, size_t readSize) {
         bool ok;
         bool expect_response = (readSize != 0);
-    
+
         ok = !_i2c->write(address, (char*)buff, writeSize, expect_response);
         if (ok && expect_response)
             ok = !_i2c->read(address, (char*)buff, readSize);
-    
+
         return ok;
     }
 
@@ -236,13 +236,13 @@
     */
     bool _read_otp(uint8_t otpAddr, void *data) {
         uint8_t optCtrl;
-        
+
         bool ok = _read_regs(SI72XX_OTP_CTRL, 1, &optCtrl)
                && !(optCtrl & OTP_CTRL__OPT_BUSY_MASK)
                && _write_reg(SI72XX_OTP_ADDR, otpAddr)
                && _write_reg(SI72XX_OTP_CTRL, OTP_CTRL__OPT_READ_EN_MASK)
                && _read_regs(SI72XX_OTP_DATA, 1, data);
-        
+
         return ok;
     }