Problems with CCS811 sensor (or i2cwrite)
Posted: Fri Mar 20, 2020 6:06 amHello,
I have a breakout board with a ccs811 and SI7021 temp/hum sensor. I wanted to write the temp und humidity data into the ENV_DATA register of the ccs81, but when I read the data again, it seems that writing the data into the register was not successful.
Output of my debug lines:
Every minute I call this function via timer:
Please see the attached file.
I have a breakout board with a ccs811 and SI7021 temp/hum sensor. I wanted to write the temp und humidity data into the ENV_DATA register of the ccs81, but when I read the data again, it seems that writing the data into the register was not successful.
Output of my debug lines:
Code: Select all
ccs811 CO2 :2985
ccs811 TVOC:393
ccs811 CO2 :4798
ccs811 TVOC:670
Humidity: 31.250 Temperature: 27.249 <-- (from SI7021)
ENV_DATA before: hum=17 0 temp=0 0 <-- reading the ENV_DATA register
bytes written 4 <-- looks good
write to ENV_DATA: hum=62 temp=52 <-- hum must be leftshifted, temp=temp+25
ENV_DATA after: hum=17 0 temp=0 0 [b]<-- *** PROBLEM ***[/b]
BMP280 Temp=27.28 QFE=1027.978
ccs811 CO2 :3173
ccs811 TVOC:422
ccs811 CO2 :4973
ccs811 TVOC:696Every minute I call this function via timer:
Code: Select all
function read_SI7021()
hum, temp, hum_dec, temp_dec = si7021.read()
print(string.format("Humidity: %d.%02d Temperature: %d.%02d", hum, hum_dec, temp, temp_dec))
css811_writeEnvData(hum, temp) <-- writing to css811
endPlease see the attached file.