BME280 sensor.

[richard]

Out of curiosity, have you tried the PBP code you posted with negative temperature values?

sorry no, i never actually used pbp for these sensors after discovering the real potential of esp chips


if the upper word was set appropriately here maybe that would help , adc_t might need similar treatment but the calculation should be
then ok ,i think?

    T1.Byte0 = IIC_RX[0]                            ' Calibration data into Unsigned Word
       T1.Byte1 = IIC_RX[1]
    T2.Byte0 = IIC_RX[2]                            ' Calibration data into Signed Long
       T2.Byte1 = IIC_RX[3]
    if  IIC_RX[3].7 then 
      T2.Byte3=255
      T2.Byte4=255
    else
      T2.Byte3=0
      T2.Byte4=0
    endif
    T3.Byte0 = IIC_RX[4]                            ' Calibration data into Signed Long
       T3.Byte1 = IIC_RX[5]
    if  IIC_RX[5].7 then 
      T3.Byte3=255
     T3.Byte4=255
   else
      T3.Byte3=0
      T3.Byte4=0
   endif

[richard]

the calculation should be
then ok ,i think?

nah, pbp needs a signed shift right command too. too hard me thinks. pic chip in bin, esp wins

[HenrikOlsson]

For anyone who are still interested in using this sensor with PBP I've posted my code as an example in the Wiki:
http://www.picbasic.co.uk/forum/cont...BME280-Example

If any questions or suggestions should pop up I suggest we keep them in this thread.

/Henrik.

[richard]

excellent work henrik, way better than my fp attempt [nearly 10k in size] to get a result.
i confirm it gets same results temp and pressure wise as arduino calcs for same input data
not tried hum yet

[richard]

henrik
i made a little change

used this style
IF P2.15 = 1 THEN
p2.highWORD = 65535
ENDIF

for all the casts to long , it saves a worthwhile bit of code space

can't test humidity on pic yet , just discovered the dishonest ebayer has sold me 4 out of 5 bmp280's in lieu of bme280 boards.
i can't tell them apart with naked eye, must admit the temp seems more accurate in absolute terms for the bmp boards there is nearly a 3 deg difference between bme and bmp readings in the same aircon'ed room and thats closer to the mercury bulb . are cheap ebay things always a bit dodgy?

[towlerg]

"are cheap ebay things always a bit dodgy?" not in my experience, most seem surprisingly interested in protecting their feedback score. Try email seller thro ebay and explain the mistake.

[richard]

Try email seller thro ebay and explain the mistake.

did that , even though i have had the boards for 2 months or more , got a full refund within a couple of hours.
quite surprised in a good way