Diff: scp1000-D01/scp1000.cpp

Revision:

2:1cc34c25b99d

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/scp1000-D01/scp1000.cpp	Fri Feb 04 11:10:22 2011 +0000
@@ -0,0 +1,153 @@
+/**
+* @section LICENSE
+*Copyright (c) 2010 ARM Ltd.
+*
+*Permission is hereby granted, free of charge, to any person obtaining a copy
+*of this software and associated documentation files (the "Software"), to deal
+*in the Software without restriction, including without limitation the rights
+*to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+*copies of the Software, and to permit persons to whom the Software is
+*furnished to do so, subject to the following conditions:
+* 
+*The above copyright notice and this permission notice shall be included in
+*all copies or substantial portions of the Software.
+* 
+*THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+*IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+*FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+*AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+*LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+*OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+*THE SOFTWARE.
+* 
+*
+* @section DESCRIPTION
+* Library for using the SCP1000-D01 MEMS Pressure sensor, this is the SPI version. This library only supports high resolution mode.
+* Communication with the sensor is via a 4 wire interface
+*
+*/
+
+#include "scp1000.h"
+
+SCP1000::SCP1000(PinName mosi, PinName miso, PinName sck, PinName CSB):
+     _spi(mosi, miso, sck),
+    _CSB(CSB)
+    {
+    _CSB = 1;
+    wait(0.1);
+    _CSB = 0;
+    //Force reset
+    _spi.write(((0x06<< 2) | 0x02));
+    _spi.write(0x01);
+    _CSB = 1;
+    wait(0.06);
+    _CSB = 0;
+    //Check starup Procedure has finished
+    int status;
+     do{
+        _spi.write(0x07 << 2);
+        status = _spi.write(0x00);
+        //printf("waiting for startup to finish %i\n", status);
+        wait(0.1);
+    }while((status & 0x01));                                  //Wait for LSB to go low
+    //Test for error in intialisation
+    _spi.write(0x1F << 2);
+    status = _spi.write(0x00);
+    if(!(status & 0x01)){
+        //printf("Error in Intialisation");
+        return;
+    }
+    
+    
+    //Set mode as 0x00
+    _spi.write((0x03 << 2) | 0x02);
+    _spi.write(0x00);
+    wait(0.05);
+    
+    //Check DRDDY is low, if not read data
+    _spi.write(0x07 << 2);
+    status = _spi.write(0x00);
+    if(status & 0x20){
+       //printf("Data to be read");
+       _spi.write(0x1F <<2);
+       _spi.write(0x00);        //read and discard data
+       _spi.write(0x20 <<2);
+       _spi.write(0x00);       //read and discard data
+       _spi.write(0x00);      //read and discard data
+    }
+    
+    //Check OPStatus bit
+    _spi.write(0x04 << 2);
+    status = _spi.write(0x0);
+    if(status & 0x01){
+        //printf("Not finished");
+    }   
+    
+    //Activate new mode
+    _spi.write((0x03 << 2) | 0x02);
+    _spi.write(0x0A);
+}
+float SCP1000::read(){
+    _CSB = 0;
+
+    if(_waitReady() == 1){ 
+        _spi.write(0x1F <<2);
+        int PressureHighest = _spi.write(0x00);
+        _spi.write(0x20 <<2);
+        int PressureHigh = _spi.write(0x00);
+        int Pressurelow = _spi.write(0x00);
+        
+        int pressureValue = Pressurelow | PressureHigh << 8 | (PressureHighest & 0x07) << 16;       
+        float pressure = ((float)pressureValue) / 4;
+ 
+        _CSB = 1;
+
+        return(pressure);
+    }else{
+        return(0);
+    }
+}
+float SCP1000::readTemperature(){
+    
+    _CSB = 0;
+    
+    if(_waitReady() == 1){ 
+        //ready so now read
+         _spi.write(0x21 << 2);
+        int TempHigh = _spi.write(0x00);
+        int TempLow = _spi.write(0x00);
+        
+        signed int temperatureValue = (TempLow | ((TempHigh & 0x1F) << 8));
+        if(TempHigh & 0x20){
+            //negative
+            temperatureValue = -8192 + temperatureValue;
+        }else{
+            //positive         
+        }
+
+        float temperature = ((float)temperatureValue) * 0.05;
+        _CSB = 1;
+        return(temperature);
+    }else{
+        return(0);
+    }
+}
+    
+ int SCP1000::_waitReady(){
+    //Depending on mode wait for it to be ready - only supports high resolution mode - wait for bit 5 to be set in 00
+    int status;
+    _CSB = 0;
+    do{
+        _spi.write(0x07 << 2);
+        status = _spi.write(0x00);
+        //printf("waiting %i\n", status);
+        wait(0.2);
+        if(status & 0x10){
+            //bit 4 high - real time error, interrupt has not been read in time - read DataRD16
+            _spi.write(0x20 << 2);
+            int data = _spi.write(0x00);
+            data = _spi.write(0x00);
+        }
+    }while(!(status & 0x20));
+    return(1);
+ }
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