Package com.diozero.devices

Class PCF8591

java.lang.Object

com.diozero.internal.spi.AbstractDeviceFactory

com.diozero.devices.PCF8591

All Implemented Interfaces:

DeviceInterface, AnalogInputDeviceFactoryInterface, AnalogOutputDeviceFactoryInterface, DeviceFactoryInterface, AutoCloseable

public class PCF8591
extends AbstractDeviceFactory
implements AnalogInputDeviceFactoryInterface, AnalogOutputDeviceFactoryInterface, DeviceInterface

Analog to Digital Converter. 4 analog in / 1 analog out.

Datasheet: http://www.nxp.com/documents/data_sheet/PCF8591.pdf.

Note the raspoid driver states there is a known bug when reading digital values from PCF8591 if analog output is disabled.

Instructions:
The jumpers control whether analog input channels of the IC are connected to the analog sources:

• Jumper P4 for AIN1: The temperature sensed by the R6 thermister is provided to the ADC.
• Jumper P5 to AIN0: The R7 photocell voltage (resistance drop) is provided to the DAC.
• Jumper P6 to AIN3: The single turn 10K ohm trimpot voltage (resistance drop ? brighter light, lower resistance).

From my experiments, the inputs / jumpers are configured as follows:

• AIN0: trimpot (P6)
• AIN1: LDR (P5)
• AIN2: ?temp? (P4)
• AIN3: AIN3

Removing a jumper allows an input channel to be fed from one of the external pins, labelled accordingly.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	PCF8591.InputMode
static class	PCF8591.PCF8591BoardPinInfo

Field Summary

Fields inherited from class com.diozero.internal.spi.AbstractDeviceFactory

closed, deviceStates

Constructor Summary

Constructors

Constructor	Description
PCF8591()
PCF8591(int controller)
PCF8591(int controller, int address, PCF8591.InputMode inputMode, boolean outputEnabled, float vRef)

Method Summary

Modifier and Type	Method	Description
void	close()	Close this device factory including all devices that have been provisioned by it.
AnalogInputDeviceInterface	createAnalogInputDevice(String key, PinInfo pinInfo)
AnalogOutputDeviceInterface	createAnalogOutputDevice(String key, PinInfo pinInfo, float initialValue)
BoardPinInfo	getBoardPinInfo()	Get information about pins that can be provisioned by this device factory.
String	getName()	Get the name of this device factory
int	getNumPins()
float	getValue(int adcPin)	Read the analog value in the range 0..1
float	getVRef()
void	setOutputEnabledFlag(boolean outputEnabled)
void	setValue(int dacPin, float value)	Set the analog output value.

Methods inherited from class com.diozero.internal.spi.AbstractDeviceFactory

createI2CKey, createPinKey, createSerialKey, createSpiKey, deviceClosed, deviceOpened, getDevice, isClosed, isDeviceOpened, reopen

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.diozero.internal.spi.AnalogInputDeviceFactoryInterface

provisionAnalogInputDevice

Methods inherited from interface com.diozero.internal.spi.AnalogOutputDeviceFactoryInterface

provisionAnalogOutputDevice

Methods inherited from interface com.diozero.internal.spi.DeviceFactoryInterface

createI2CKey, createPinKey, createSerialKey, createSpiKey, deviceClosed, deviceOpened, getDevice, isClosed, isDeviceOpened, reopen, start

Constructor Detail

PCF8591

public PCF8591()

PCF8591

public PCF8591(int controller)

PCF8591

public PCF8591(int controller,
               int address,
               PCF8591.InputMode inputMode,
               boolean outputEnabled,
               float vRef)

Method Detail

getVRef

public float getVRef()

Specified by:

getVRef in interface AnalogInputDeviceFactoryInterface

getBoardPinInfo

public BoardPinInfo getBoardPinInfo()

Description copied from interface: DeviceFactoryInterface

Get information about pins that can be provisioned by this device factory.

Specified by:

getBoardPinInfo in interface DeviceFactoryInterface

Returns:

board pin info instance for this device factory

close

public void close()
           throws RuntimeIOException

Description copied from interface: DeviceFactoryInterface

Close this device factory including all devices that have been provisioned by it.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface DeviceFactoryInterface

Specified by:

close in interface DeviceInterface

Overrides:

close in class AbstractDeviceFactory

Throws:

RuntimeIOException

getName

public String getName()

Description copied from interface: DeviceFactoryInterface

Get the name of this device factory

Specified by:

getName in interface DeviceFactoryInterface

Returns:

the name of this device factory

createAnalogInputDevice

public AnalogInputDeviceInterface createAnalogInputDevice(String key,
                                                          PinInfo pinInfo)
                                                   throws RuntimeIOException

Specified by:

createAnalogInputDevice in interface AnalogInputDeviceFactoryInterface

Throws:

RuntimeIOException

createAnalogOutputDevice

public AnalogOutputDeviceInterface createAnalogOutputDevice(String key,
                                                            PinInfo pinInfo,
                                                            float initialValue)
                                                     throws RuntimeIOException

Specified by:

createAnalogOutputDevice in interface AnalogOutputDeviceFactoryInterface

Throws:

RuntimeIOException

getValue

public float getValue(int adcPin)
               throws RuntimeIOException

Read the analog value in the range 0..1

Parameters:

adcPin - Pin on the MCP device

Returns:

The unscaled value (0..1)

Throws:

RuntimeIOException - if an I/O error occurs

setValue

public void setValue(int dacPin,
                     float value)
              throws RuntimeIOException

Set the analog output value.

Parameters:

dacPin - The analog output channel.

value - Analogue output value (0..1).

Throws:

RuntimeIOException - if an I/O error occurs

getNumPins

public int getNumPins()

setOutputEnabledFlag

public void setOutputEnabledFlag(boolean outputEnabled)