Wire.requestFrom(address, quantity, stop) Parameters address: The 7-bit address of the device from which to request bytes. Syntax Wire.requestFrom(address, quantity) The bytes may then be retrieved with the available() and read() functions. Syntax Wire.begin() Parameters None Returns None requestFrom Description Used by the master to request bytes from a slave device.
Wire: 21(SCL), 20(SDA) begin Description Initiates the Wire library. Not supported for operating as a slave device. The available channels and pin numbers are as follows and can also be confirmed on the pin map. The pull-up to communication lines is needed. / Experiment of PCF8574 IO expander // Name:- M.This is an I 2C communications library that facilitates two-wire class communications with I 2C/TWI devices (also called "Wire Library"). The project is successfully simulated by using the Proteus. Upper nibble is configured as output and connected with 4 LEDs. Lower nibble is configured as inputs, and connected with 4 way dip switch. Lower nibble of Group 2 IO expander is read and displayed at upper nibble of the same IO expander. The binary counter is incremented by every 300 mS and writes it to the Group 1 IO expander, where LEDs are connected and configured as digital output pins. The included Wire library allows to communicate to the I2C/TWI bus of Arduino. Commonly used to select the operating modes of an electronic device for specific situations.Ī 4 way DIP switch is connected to the lower nibble of PCF8574 Group2 device IO pins through 10K ohm pullup resistors.Īnd 4 LEDs are connected to the upper nibble of PCF8574 Group2 device IO pins through 330 ohm current limiting resistors. The 8 LED’s are connected to the PCF8574 Group1 device IO pins through 330 ohm current limiting resistors.ĭIP switches are manual electrical switches arranged and packed in Dual Inline Package. The least significant bit of address is used for Write (0) or Read (1) operation selection.Įight PCF8574 can be connected to the I2C bus, with hardwire address selection on each device.
The Address range of PCF8574 is 0x20 to 0x27 (7 bit address mode). The device features an 8-bit quasi-bidirectional I/O port (P0–P7), including latched outputs with high current drive capability for directly driving LEDs.Įach quasi-bidirectional I/O can be used as an input or output without the use of a data-direction control signal. The PCF8574 device provides general-purpose remote I/O expansion.
I2C data pin (SDA) is connected to ADC4 and clock pin (SCL) is connected to ADC5. PCF8574 is the Input / Output (I/O) expander, which will be connected to the Arduino I2C bus.
0 kommentar(er)
