micropython/drivers/sensor/pasco2: Adding support for IFX-PASCO2 sensor.

Signed-off-by: NikhitaR-IFX <Nikhita.Rajasekhar@infineon.com>

micropython/drivers/sensor/pasco2/manifest.py

@@ -0,0 +1,3 @@
+metadata(description="Driver for XENSIV PAS CO2 sensor.", version="0.1.0")
+
+module("pasco2.py", opt=3)

micropython/drivers/sensor/pasco2/pasco2.py

@@ -0,0 +1,107 @@
+from machine import I2C
+from utime import sleep, sleep_ms
+
+# Sensor Register Address Stack
+#_PASCO2_REG_PROD_ID        = const(0x00) # Product and revision ID register address
+_PASCO2_REG_SENS_STS       = const(0x01) # Sensor status register address  
+_PASCO2_REG_MEAS_RATE_H    = const(0x02) # Measurement period MSB configuration register address  
+#_PASCO2_REG_MEAS_RATE_L    = const(0x03) # Measurement period LSB register address  
+_PASCO2_REG_MEAS_CFG       = const(0x04) # Measurement mode configuration register address  
+_PASCO2_REG_CO2PPM_H       = const(0x05) # CO2 concentration result MSB register address  
+#_PASCO2_REG_CO2PPM_L       = const(0x06) # CO2 concentration result LSB register address  
+_PASCO2_REG_MEAS_STS       = const(0x07) # Measurement status register address  
+#_PASCO2_REG_INT_CFG        = const(0x08) # Interrupt pin configuration register address  
+#_PASCO2_REG_ALARM_TH_H     = const(0x09) # Alarm threshold MSB register address   
+_PASCO2_REG_SENS_RST       = const(0x10) # Soft reset register address  
+    
+#Error codes
+_PASCO2_SUCCESS = 0
+_PASCO2_ERROR = -1
+
+addr = 0
+mask = 1
+
+i2c = I2C(0)
+
+class PASCO2:
+    """IFX - XENSIV PAS CO2 sensor driver"""
+    regMap = { # RegAddr, Mask
+    'REG_SENS_STS_BITF_SENS_RDY' : [_PASCO2_REG_SENS_STS, 0x80],
+    'REG_MEAS_CFG_BITF_OP_MODE'  : [_PASCO2_REG_MEAS_CFG, 0x03],
+    'REG_MEAS_STS_BITF_DATA_RDY' : [_PASCO2_REG_MEAS_STS, 0x10], # Data ready status bit
+    'REG_CO2PPM_H_BITF_CO2_PPM_H': [_PASCO2_REG_CO2PPM_H, 0xFF],
+    }
+    
+    def __init__(self, bus, measInterval=10, sensorAddr=0x28):
+        self.bus = bus
+        self.sensorAddr = sensorAddr
+        self.measInterval = measInterval
+        self.softResetCode = b"\xa3"
+        
+    def _read_reg(self, regAddr, bytesToRead=1):
+        readVal = self.bus.readfrom_mem(self.sensorAddr, regAddr, bytesToRead)
+        return readVal
+    
+    def _write_reg(self, regAddr, writeData):
+        self.bus.writeto_mem(self.sensorAddr, regAddr, writeData)
+    
+    def _is_sensor_ready(self):
+        reg = self.regMap['REG_SENS_STS_BITF_SENS_RDY']
+        return (self._read_reg(reg[addr])[0] & reg[mask])
+    
+    def _soft_reset(self):
+        self._write_reg(_PASCO2_REG_SENS_RST, self.softResetCode)
+        
+    def _set_mode(self, mode):
+        if mode == 'idle': modeVal = 0x00
+        if mode == 'continuous': modeVal = 0x02
+        
+        reg = self.regMap['REG_MEAS_CFG_BITF_OP_MODE']
+        readData = self._read_reg(reg[addr])[0]
+        writeData = bytes([(readData & ~(reg[mask])) | modeVal])
+        self._write_reg(_PASCO2_REG_MEAS_CFG,writeData)
+        
+        
+    def initialize(self):
+        try:
+            # wait for sensor to be ready
+            sensor_ready = self._is_sensor_ready()
+            while not sensor_ready:
+                sleep(1)
+                sensor_ready = self._is_sensor_ready()
+
+            # soft reset sensor register
+            self._soft_reset()
+            sleep_ms(800)
+
+            # set measure rate
+            buf = bytes([(self.measInterval >> 8) & 0xFF, self.measInterval & 0xFF])
+            self._write_reg(_PASCO2_REG_MEAS_RATE_H, buf)
+
+            # reset operation mode to idle mode
+            self._set_mode('idle')
+    
+            # start continuous mode
+            self._set_mode('continuous')   
+    
+            return _PASCO2_SUCCESS
+
+        except:
+            return _PASCO2_ERROR
+    
+    def getCO2Value(self):
+        while True:
+            try: 
+                # get meas status
+                reg = self.regMap['REG_MEAS_STS_BITF_DATA_RDY']
+                readStatus = self._read_reg(reg[addr])
+                data_ready = readStatus[0] & reg[mask]
+
+                if data_ready:    
+                    # get CO2 value
+                    reg = self.regMap['REG_CO2PPM_H_BITF_CO2_PPM_H']
+                    readVal = self._read_reg(reg[addr], 2)
+                    co2_value = (readVal[0] << 8) | readVal[1]
+                    return co2_value
+            except:
+                return _PASCO2_ERROR