BPM280 to Lora Explorer through SPI

1

Hi, does anyone know how to connect BPM280 to Lora Explorer. The sensor has an SPI socket, not I2C! Do you have instruction for SPI (physical connections, libraries…), i do not want to damage the board.

thanks lot.

2

what board is that ? sodaq ? you have a link

seems that you have a lot of 'problems with your node

3

@bantob Reading the spec sheet for the BPM280 sensor it can connect by both I2C and SPI using the same pins on the sensor. To select I2C the CSB pin on the sensor must be connected to VDDIO. This method is common to a number of the Bosch sensors.

4

I have just been going through the various BME280\BMP280 sensor libraries that are available for Arduino, too see which had the smallest flash\ram requirement.

All the sensor boards I have bought are low cost from eBay. All the libraires ands sensors assume and use I2C by default. I guess you could use SPI if you wanted to.

5

thanks. do you have a link to the connection shematics?

6

ok, my issue is to see how can be connected to SPI and what libs to import.

7

yes sodaq

8

Here we go, this page by Bosch gives links to Datasheets, Application Notes etc. Follow the Tab to Downloads. Have a look at the data sheet and search for using I2C. see Section 5.2 on page 28. https://www.bosch-sensortec.com/bst/products/all_products/bme280

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thanks lot!
So i believe the important part to use the BMP280 with I2C is the following (page 33):

  • SCK : serial clock (SCL)
  • SDI : data (SDA)
  • SDO: slave address LSB

am i right?
thans

11

Yes, that’s correct
* SCK : serial clock (SCL)
* SDI : data (SDA)

if SDO = Ov then the I2C address is 76Hex and if SDO = Vddio then the I2C address is 77Hex

Pin Connections to the BME280
1 Ground - 0 Volt of the power supply
2 CSB - connect to Vddio which is pin 6 - this sets the output pins to work as I2C
3 I2C SDA - this is the I2C Data
4 I2C SCL - this is the I2C Clock
5 SDO (connect to Ground or 0 Volt on Pin 1 then the I2C address is 76Hex and if SDO = Vddio on Pin 6 then the I2C address is 77Hex
6 Vddio this is the voltage supply to the output pins - connect to 3.3 Volt Supply
7 Ground - 0 Volt (connect this to Pin 1)
8 Vdd this is the power supply to the sensor part of the chip - connect to 3.3 volt supply (connected to pin 6)

12

thanks.
I am bit confused on the pin mapping you have listed. I am using SODAQ and BMP280 (i counte 7 pins overall). Are you referring to that schematic?

Furthermore by looking in more details i think i can connect the sensor via SPI directly…
http://support.sodaq.com/sodaq-one/explorer/

13

The pins I am listing are from the BME280. in total there will be 4 wires from the BME280 to the sodaq board, they are 3.3v, 0v, SDA and SCL. You can find them on the Sodaq board. SDA and SCL are on the top right of the board (refer to your link), 0V is the 4th down from the top on the right hand side, and 3.3v is on the left side of the board.
I’m looking at the BME280 device which is 2.5mm x 2.5mm, this device has 8 connections on the bottom. Two of them are 0v. If you have a breakout board, ie the BMP280 soldered to a small PCB then there may only be 7 connections to this PCB.

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