ch.aplu.ev3

Class I2CExpander

java.lang.Object

ch.aplu.ev3.Part

ch.aplu.ev3.Sensor

ch.aplu.ev3.I2CExpander

public class I2CExpander
extends Sensor

Class that represents one of the standard I2C expander ICs. The EV3 acts as master and the the expander as slave.

Constructor Summary

Constructors

Constructor and Description
I2CExpander() Creates a sensor instance connected to sensor port 1.
I2CExpander(SensorPort port) Creates a sensor instance connected to the given port.
I2CExpander(SensorPort port, int deviceType, int slaveAddress8bit) Creates a sensor instance connected to the given port and selects device type and I2C address of attached device.
I2CExpander(SensorPort port, int deviceType, int inputMode, int slaveAddress8bit) Creates a sensor instance connected to the given port and selects devivce type, input mode and I2C address of attached device.

Method Summary

Methods

Modifier and Type	Method and Description
int[]	readAnalog() Reads all analog inputs at same time (8 bit ADC).
int	readAnalog(int channel) Reads one analog input channel (8 bit ADC).
int	readAnalogInt() Reads all analog inputs at same time (8 bit ADC).
void	setAnalogInputMode(int inputMode) Sets the input mode for the PCF8591 device.
void	setup(int deviceType, int slaveAddress8bit) Selects device type and I2C address of attached device.
void	writeAnalog(int out) Sets the output voltage of the 8-bit DAC.
int	writeDigital(int out) Writes one byte data to the output and reads back the result.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

I2CExpander

public I2CExpander(SensorPort port)

Creates a sensor instance connected to the given port. Call setup() to set the device type and I2C address.

Parameters:

port - the port where the sensor is plugged-in

I2CExpander

public I2CExpander()

Creates a sensor instance connected to sensor port 1. Call setup() to set the device type and I2C address.

I2CExpander

public I2CExpander(SensorPort port,
           int deviceType,
           int inputMode,
           int slaveAddress8bit)

Creates a sensor instance connected to the given port and selects devivce type, input mode and I2C address of attached device. Supported device types: 0: PCF8574, 1: PCF8574A, 2: PCF8591 Supported device modes for PCF8591: 0: Four single ended inputs, 1: Three differential inputs, 2: Single ended and differential mixed, 3: Two differential inputs (see PCF8591 data sheet for more information). Keep in mind to set unused analog inputs to defined level.

For compatibility with other leJOS I2C devices, the 8-bit I2C addressing is used, where the LSB is always 0 and the 7 standard I2C address bits A0..A6 are arranged in a byte as follows:
A6 A5 A4, A3 | A2 A1 A0 0

Parameters:

port - the port where the sensor is plugged-in

deviceType - expander type

inputMode - expander input mode (for PCF8591)

slaveAddress8bit - the 8 bit I2C address of the device

I2CExpander

public I2CExpander(SensorPort port,
           int deviceType,
           int slaveAddress8bit)

Creates a sensor instance connected to the given port and selects device type and I2C address of attached device. The default input mode 0 is used (single ended). Supported device types: 0: PCF8574, 1: PCF8574A, 2: PCF8591 For compatibility with other leJOS I2C devices, the 8-bit I2C addressing is used, where the LSB is always 0 and the 7 standard I2C address bits A0..A6 are arranged in a byte as follows:
A6 A5 A4, A3 | A2 A1 A0 0

Parameters:

port - the port where the sensor is plugged-in

deviceType - expander type

slaveAddress8bit - the 8 bit I2C address of the device

Method Detail

setup

public void setup(int deviceType,
         int slaveAddress8bit)

Selects device type and I2C address of attached device. For compatibility with other leJOS I2C devices, the 8-bit I2C addressing is used, where the LSB is always 0 and the 7 address bits A0..A6 are arranged in a byte as follows:
A6 A5 A4, A3 | A2 A1 A0 0

Parameters:

deviceType - expander type; supported devices. 0: PCF8574, 1: PCF8574A, 2: PCF8591

slaveAddress8bit - the 8 bit I2C address of the device

writeDigital

public int writeDigital(int out)

Writes one byte data to the output and reads back the result. Returns the current data. To define a port pin as input, write the bit value 1 to the port pin. On power on all pins are pulled to VDD with approx. 50 kOhm.
Digital output: If 0 is written to port pin, the max. pull-down current is 10 mA.
Digital input: 1 must be written to port pin. The attached electronics pulls this port either to ground (GND) or VCC. Input current is approx. 100 uA for LO input (impedance approx. 50 kOhm) and infinite impedance for HI input.

Parameters:

out - Digital out: 0 for digital out - LO state, 1 for digital out - HI state. Digital in: 1 must be written to the port pin and the external electronics pulls the pin to LO or HI.

Returns:

the current state of the port bits: 0 for LO, 1 for HI; -1 if the device does not support digital in/out. An integer is returned that represents the unsigned byte

writeAnalog

public void writeAnalog(int out)

Sets the output voltage of the 8-bit DAC.

Parameters:

out - 0..255 converted to 0..VCC

setAnalogInputMode

public void setAnalogInputMode(int inputMode)

Sets the input mode for the PCF8591 device. Supported input modes: 0: Four single ended inputs, 1: Three differential inputs, 2: Single ended and differential mixed, 3: Two differential inputs (see PCF8591 data sheet for more information). Keep in mind to set unused analog inputs to defined level.

Parameters:

inputMode - the input mode (0, 1, 2, 3)

readAnalog

public int[] readAnalog()

Reads all analog inputs at same time (8 bit ADC). The returned values are in 0..255 for single ended inputs and -128..127 for differential inputs. For device mode 0, channels 0..3 are returned, for mode 1 and 2, channels 0..2 are returned, for mode 3, channels 0..1 are returned.

Returns:

the current input voltages 0..VCC digitized to 8 bits

readAnalogInt

public int readAnalogInt()

Reads all analog inputs at same time (8 bit ADC). The returned values are in 0..255 for single ended inputs and -128..127 for differential inputs. For device mode 0, channels 0..3 are returned, for mode 1 and 2, channels 0..2 are returned, for mode 3, channels 0..1 are returned.

Returns:

the current input voltages 0..VCC digitized to 8 bits and packed into a 32 bit integer with channel 0 at LSB

readAnalog

public int readAnalog(int channel)

Reads one analog input channel (8 bit ADC). The returned value is in 0..255 for single ended input and -128..127 for differential input.

Returns:

the current input voltage 0..VCC digitized to 8 bits.