Revision 3:423f2830684e, committed 2022-01-03

Comitter:

rollman

Date:

Mon Jan 03 02:40:16 2022 +0000

Parent:

2:ec392b3a49f2

Commit message:

initial commit;

Changed in this revision

--- a/CCS811.cpp	Thu Mar 05 08:27:24 2020 +0000
+++ b/CCS811.cpp	Mon Jan 03 02:40:16 2022 +0000
@@ -155,6 +155,37 @@
     return i2c_buf[0];
 }
 
+int CCS811::setEnvironment(float celsius, float humidity){
+    uint8_t humh = convertCCSFixedPointUpper(humidity);
+    uint8_t huml = convertCCSFixedPointLower(humidity);
+    uint8_t tmph = convertCCSFixedPointUpper(celsius+25);
+    uint8_t tmpl = convertCCSFixedPointLower(celsius+25);
+
+    {
+        char i2c_buf[5];
+        i2c_buf[0] = CCS811_REG_ENV_DATA;
+        i2c_buf[1] = humh;
+        i2c_buf[2] = huml;
+        i2c_buf[3] = tmph;
+        i2c_buf[4] = tmpl;
+        m_i2c.write(CCS811_I2C_ADDR, i2c_buf, 5);
+    }
+    
+    int status = readStatus();
+    int err;
+    if((status & 1) != 0) {
+        char i2c_buf[2];
+
+        i2c_buf[0] = CCS811_REG_ERROR_ID;
+        m_i2c.write(CCS811_I2C_ADDR, i2c_buf, 1);
+        m_i2c.read(CCS811_I2C_ADDR, i2c_buf, 1);
+        err = i2c_buf[0];
+        return err;
+    }else{
+        return 0;
+    }
+}
+
 int CCS811::readStatus(){
     char i2c_buf[2];
     
@@ -164,6 +195,30 @@
     return i2c_buf[0];
 }
 
+uint8_t CCS811::convertCCSFixedPointUpper(float x){
+    uint8_t upper = int(x) << 2;
+    float frac = x - int(x);
+    if(frac * 2 >= 1.0){
+        upper = upper | 1;
+    }
+    return upper;
+}
+
+uint8_t CCS811::convertCCSFixedPointLower(float x){
+    uint8_t lower = 0;
+    float frac = x - int(x);
+    frac *= 2;
+    if(frac >= 1.0) frac -= 1;
+    for(int i = 7; i >= 0; i--) {
+        frac *= 2;
+        if(frac >= 1.0) {
+            lower = (lower | (1 << i));
+            frac -= 1.0;
+        }
+    }
+    return lower;
+}
+
 void printerr(Serial& m_pc, int errid){
     if (errid == CCS811_ERR_HWID){
         m_pc.printf("CCS811_ERR_HWID\r\n");

--- a/CCS811.h	Thu Mar 05 08:27:24 2020 +0000
+++ b/CCS811.h	Mon Jan 03 02:40:16 2022 +0000
@@ -51,6 +51,7 @@
         CCS811(I2C& i2c, Serial &pc);
         int init();
         int setMeasureMode(char mode);
+        int setEnvironment(float celsius, float humidity);
         int readData(uint16_t *ECO2, uint16_t *TVOC);
         bool checkHW();
         bool softRest();
@@ -60,6 +61,8 @@
         I2C m_i2c;
         Serial m_pc;
     private:
+        uint8_t convertCCSFixedPointUpper(float x);
+        uint8_t convertCCSFixedPointLower(float x);
 };
 
 void printerr(Serial& m_pc, int errid);