28018 Parallax Inc, 28018 Datasheet - Page 7

• Manufacturer Part Number: 28018
• Description: MODULE SENSOR TEMP+HUMIDITY
• Manufacturer: Parallax Inc
• Series: Sensirion SHT11r

Specifications of 28018

• Output Type: Digital - 2-Wire
• Sensor Type: Humidity and Temperature
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

' returns "status"
'
SHT_Read_Status:
' sends "ioByte"
' returns "ackBit"
'
SHT_Write_Byte:
' returns "ioByte"
' sends "ackBit"
'
SHT_Read_Byte:
' wait for device to finish measurement (pulls data line low)
' -- timeout after ~1/4 second
'
SHT_Wait:
Parallax, Inc. • Sensirion SHT11 Sensor Module (#28018) • 07/2003
GOSUB SHT_Write_Byte
ioByte = status
GOSUB SHT_Write_Byte
RETURN
GOSUB SHT_Start
ioByte = ShtStatW
GOSUB SHT_Read_Byte
ackBit = NoAck
GOSUB SHT_Read_Byte
RETURN
SHIFTOUT ShtData, Clock, MSBFirst, [ioByte]
SHIFTIN
RETURN
SHIFTIN
SHIFTOUT ShtData, Clock, LSBFirst, [ackBit\1] ' send ack bit
INPUT ShtData
RETURN
INPUT ShtData
timeOut = No
FOR toDelay = 1 TO 250
NEXT
IF (toDelay = 250) THEN timeOut = Yes
RETURN
IF (ShtData = 0) THEN EXIT
PAUSE 1
ShtData, Clock, LSBPre, [ackBit\1]
ShtData, Clock, MSBPre, [ioByte]
' send command
' alert device
' write to status reg cmd
' send command
' only one byte to read
' send byte
' get ack bit
' get byte
' release data line
' data line is input
' assume no timeout
' wait ~1/4 second
' loop completed = timeout
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