Hi, I have encountered a strange behavior of BME680 multivariable sensor(s) (as it happened to all 3 pieces I have). The sensor is correctly supplied (3,3 V, no voltage sags, both VDD and VDDIO pins shorted together, low impedance GND connection) and interfaced via I2C (communication 100% correct). When I measure temperature, humidity and pressure the sensor triggers correctly and the response obtained via I2C is very accurate. But when gas sensing feature is enabled (via RUN_GAS bit in CTRL_GAS_1 register) the sensor behaves in a strange way. The 0th gas sensor heater set point is used, heater temperature and heating time registers contain: GAS_WAIT_0 10111110 RES_WAIT_0 11010000 When MODE bit in CTRL_MEAS register is set to 1 the sensor correctly sets MEASURING flag in MEAS_STATUS_0 register to 1. But then, after approx. 11 ms some registers are set to 11111111 and then, after another 3,8 ms (it is the fastest time graduation I was able to obtain to log register states) gas-related registers are reset to 0. Here is the log of gas-sensing-related registers: CTRL_GAS_1 IDAC_HEAT_0 GAS_R_LSB GAS_WAIT_0 RES_WAIT_0 CTRL_MEAS MEAS_STATUS_0 ---- 10000 0 100 10111110 11010000 100101 100000 -- 10000 0 100 10111110 11010000 100101 100000 -- 11111111 11111111 11111111 11111111 11111111 11111111 0 -- 0 0 100 0 0 0 0 -- 0 0 100 0 0 0 0 I was also monitoring the sensor supply current using a wideband current clamp probe and a scope but no current jump, related to heater turn-on was registered. Any idea what is happening ? Any help or suggestion would be highly appreciated. Best regards, Pawel
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