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Wiring_of_Board.md

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I2C interfaces

I2C_1 D1 D2 [5,4] 400kHz with extra clock stretch limit

  • SGP30
  • BME680
  • MAX30105
  • CCS811 (needs extra clock stretch of 100ms)
  • all breakout boards have 5-10k pullup

I2C_2 D3 D4 [0,2] 100kHz with extra clock stretch limit

  • SPS30 with 5V power and 10k pullup to 3.3V, particle sensor, sensor can crash and only recovers after disconnecting power
  • SCD30, CO2 sensor (most unusual i2c requirements, signal high is 2.4V, needs extra clock stretch limit 150ms, and prefers slow clock)
  • needs 5k pullup

I2C_3 D5 D6 [14,12] 100kHz no extra clock stretch limit

  • LCD after 5V Level Shifter, this sensor affects, operation of other sensors
  • MLX90614 5V Level Shifter if you have 5V vesion, this sensor might be affected by other breakout boards and erroniously reports negative temp and temp above 500C, this can be recovered in software
  • Level shifter has 5k pullup, MLX has no pullup

Wake and Interrupt Pin assignements

  • D8 [15]: SCD30_RDY interrupt, goes high when data available, remains high until data is read, this requires the sensors to be power switched after uploadiong new program to ESP, if the sensor has data available, the pin is high and the mcu can no longer be programmed

  • D0 [16]: CCS811_Wake, needs to be low when communicating with sensors, most of the time its high

  • D7 [13]: CCS811_INT, goes low when data is available, most of the time its high, needs pull up configuration via software

  • CCS811 address pin needs to be set to high which is accomplished with connecting adress pin to 3.3V signal

Wiring

BME280 rH, p, T, resistance

Pin Connection
SDA D2
SCL D1
GND GND
VCC 3.3V
SD0 N.C. or GND, default address 0x76
CSB N.C. or 3.3V active high, active high

BME680 rH, p, T, resistance

Pin Connection
SDA D2
SCL D1
GND GND
VCC 3.3V
SD0 3.3V alternate address 0x77
CS N.C. or 3.3V active high, active high

CCS811 tVOC eCO2

Pin Connection
SDA D2
SCL D1
GND GND
VCC 3.3
CCS811_WAKE D0 active low
CCS811_INT D7 active low
CCS811_Address 3.3V address us 0x5B
CCS811_RST N.C. active low

Display

Pin Connection
VCC 5V
GND GND
SDA D6 5V with level shifter
SCL D5 5V with level shifter

SPS30 particulate

Pin Connection
VIN 5V
GND GND
SDA D4 3.3V
SCL D3 3.3V
SEL GND for i2c

SCD30 CO2

Pin Connection
VDD 3.3V
GND GND
SCL D3
SDA D4
RDY D8 input, active high
SEL GND for i2c

SGP30 tVOC eCO2

Pin Connection
VDD 3.3
GND GND
SCL D1
SDA D2