Can T-Beam connect to BMP280?

[LilyGO]

As the title. If the program has extended the BMP280 function, the connection pin is 21 and 22.

[lyusupov]

This is valid for T-Beam board with h/w rev. t22_v05 or higher only!  ¹

Effective from version 1.0-RC5, SoftRF firmware has (not announced yet) support for two I2C buses on TTGO T-Beam (v05+).

Pin numbers are:

// 1st I2C bus on the T-Beam v05+
#define SOC_GPIO_PIN_TBEAM_SDA  13
#define SOC_GPIO_PIN_TBEAM_SCL  2

// Hardware pin definitions for TTGO V2 Board with OLED SSD1306 0,96" I2C Display
#define TTGO_V2_OLED_PIN_RST  U8X8_PIN_NONE // connected to CPU RST/EN
#define TTGO_V2_OLED_PIN_SDA  21
#define TTGO_V2_OLED_PIN_SCL  22

Barometric pressure sensor is allowed on either:

• 1st I2C bus (2/13) or
• 2nd I2C bus (21/22)

OLED is allowed on 2nd I2C bus (21/22) only.

Because of the GPIO2 is one of the ESP32 "strapping" pins, 1st bus has one hardware design limitation, see this ticket for more details.

Recommendations:

1) If the BMP280 module is the only I2C device to be connected - wire it to 2nd bus (21/22) 2) if the OLED module is the only I2C device to be connected - wire it to 2nd bus (21/22) 3) if you need to have both BMP280 and OLED:

• wire the BMP into 1st bus (2/13) ;

  • wire the OLED into 2nd bus (21/22) but be ready to disconnect at least GPIO2 pin/wire from the BMP280 every time you want to install or update any firmware via micro-USB cable.

    ¹     T-Beam t22_v02 has status LED on GPIO21 - this makes 2nd I2C bus to be inoperative on this pin number. 1st bus (2/13) should be Ok for BMP280 on t22_v02, but it was not tested at all !

[LilyGO]

Thank you very much