Technical specifications
- Manufacturer
- Bosch Sensortec / module vendor
- MCU / Part
- BME280
- Architecture
- Digital MEMS sensor
- Logic voltage
- 1.8–3.6 V bare sensor; breakout dependent
- Recommended input
- Breakout dependent
- GPIO limits
- Do not apply 5 V to bare sensor pins
- Flash
- N/A
- RAM
- N/A
- Clock
- Host bus clock limits per datasheet
- ADC
- Internal sensing ADC
- DAC
- None
- PWM / timers
- None
- Connectivity / buses
- I²C or SPI
- Programmer
- N/A
- Debugger
- I²C/SPI logic analyser
Pin reference
| Pin | Type | Main functions | Electrical note |
|---|
| VDD/VDDIO | Power | Core/interface supplies | Bare sensor voltage limits apply |
| SDA/SDI | Digital | I²C data or SPI MOSI | Pull-up for I²C |
| SCL/SCK | Digital | I²C/SPI clock | Logic at VDDIO |
| SDO | Digital | SPI MISO / I²C address select | Do not float in I²C design |
| CSB | Digital | SPI chip select / I²C mode select | Set for chosen bus |
| GND | Power | Ground | Common ground required |
Features and compatibility
Pressure, humidity, temperature, low power
Many breakout boards include regulators and level shifting, but not all. Identify the exact module before using 5 V.
Open official datasheet/documentation ↗Deep reference
Architecture, electrical limits and engineering guidance
- Exact MCU / SoC
- BME280
- Maximum GPIO current
- Do not apply 5 V to bare sensor pins
- EEPROM / NVM
- Use internal data flash/NVS/flash emulation where supported; include wear levelling and power-fail protection.
- Interrupts / DMA
- GPIO/peripheral interrupts are available. DMA capability is device-specific; confirm channels, request mapping and memory-access restrictions in the reference manual.
- Sleep and power
- Use the light/deep/standby modes offered by the device. Measure board current because regulators, LEDs and USB interfaces can dominate MCU sleep current.
- Boot and programming
- Confirm boot-mode pins before reset. Use the official bootloader/programmer and retain a recoverable debug/programming header.
Special and restricted pins
Reset, clock, debug, USB, crystal and analogue-reference pins have special electrical or boot functions. Avoid loading them until the boot sequence is understood.
Boot-strapping warnings
Check BOOT/RESET/programming pin truth tables before assigning peripherals; keep required pull resistors fitted.
I/O voltage warnings
1.8–3.6 V bare sensor; breakout dependent domain. Never exceed VDD + permitted injection limits; level-shift incompatible modules and share ground only where safe.
Memory map and registers
Start with the memory map: code flash, SRAM, peripheral registers and system/control space. Use vendor headers instead of hard-coded addresses, then study GPIO direction/output/input, clock-enable, interrupt and timer registers.
Board-selection guidance
Choose this device only after checking logic voltage, required interfaces, memory margin, timers/ADC resolution, debugging access, package availability and long-term tool support.
Common faults and troubleshooting
Not detected: verify data USB cable, driver, boot mode and target power. Upload failure: select the exact target and programmer. Unstable operation: inspect supply ripple, reset, clock and watchdog cause. Wrong readings: check reference voltage, grounding, pin multiplexing and calibration.
Interview and viva questions
What is the difference between an absolute maximum and an operating limit?
Absolute maximum prevents damage; reliable design stays within recommended operating conditions.
Why must peripheral clocks be enabled?
Many MCUs gate clocks to save power; registers may not operate until the peripheral clock is enabled.
Why preserve a debug interface?
It enables programming, breakpoints, fault inspection and production recovery.
What causes GPIO damage?
Over-voltage, excess source/sink current, negative injection, ESD or driving against another output.
