The GAS values is slow to update and is not accurate

[saraceni-andrea]

https://forums.adafruit.com/viewtopic.php?f=60&t=132231

[mod edit - removed key word highlighting from url]

[caternuson]

Probably related to #11

[saraceni-andrea]

Also on SPI no improvement ... :-(
https://forums.adafruit.com/viewtopic.php?f=60&t=132231&p=736089&hilit=bme680#p736089

[ladyada]

not surprising, the SPI is still reading the same data. you could try to compare what the arduino or espruino is sending for commands and let us know if you see any differences in data?

[markpatterson27]

Someone correct me if I'm wrong, but it looks like the gas heating duration isn't being set.

Adafruit_CircuitPython_BME680/adafruit_bme680.py

Lines 107 to 108 in f1b9e6c

	# set up heater
	self._write(_BME680_BME680_RES_WAIT_0, [0x73, 0x64, 0x65])

If I understand _write() correctly, the above is just writing [0x73, 0x64, 0x65] into incrementing registers 0x5A to 0x5C and not setting the heating duration. It should be changed to something like:

        _BME680_BME680_RES_HEAT_0 = const(0x5A)
        _BME680_BME680_GAS_WAIT_0 = const(0x64)

        self._write(_BME680_BME680_RES_HEAT_0, [0x73])   # approx 320 degrees
        self._write(_BME680_BME680_GAS_WAIT_0, [0x65])   # 148ms

[saraceni-andrea]

Hi, the latest update of adafruit_bme680.py (release 3.1.3) on CircuitPython 5.0 and Bundle 20200307 works perfectly!

Tested via i2c on:

• Feather M4 Express
• ItsyBitsy M4
• Trinket M0

THANK YOU VERY MUCH