Library for PCF8575 I2C Expander

Library for PCF8575 I2C Expander

PCF8575 is 16-bit I/O expander for the two-line bidirectional bus (I2C). It features 16-bit quasi-bidirectional I/O port, P07-P00 and P17-P10. It can easily be switched from output to input; write I/O with “1” to be used as an input. Quasi-bidirectional means that outputs can be used both as an input and output without the need to reconfigure the port. There are 8 address combinations (A2 A1 A0) so it is possible to have eight I2C expanders on same I2C bus. Connection PCF8575 – STM32 is plain simple. There is no need for external pull-up resistors…

Library for BMP085 Digital Pressure Sensor

Library for BMP085 Digital Pressure Sensor

Bosch’s BMP085 is a digital pressure sensor. It is designed to be connected directly to a microcontroller via the I2C bus. I2C is a synchronous two-wire interface. The first wire, SDA, is used for data transmission, while second wire, SCL, transmits a clock, which is used to keep track of the data. It features pressure measuring range of 300-1100 hPa (Pascal Unit) and temperature measurement from 0 to 65 °C. BMP085 – STM32F4 connection is pretty straight forward. The only thing which needs attention is how you power the sensor. Its maximum supply voltage is 3.6V so…