net.sf.jaer.biasgen
Class IPot

java.lang.Object
  java.util.Observable
      net.sf.jaer.biasgen.Pot
          net.sf.jaer.biasgen.IPot

All Implemented Interfaces:

java.lang.Cloneable, java.util.EventListener, java.util.Observer, java.util.prefs.PreferenceChangeListener, RemoteControlled

Direct Known Subclasses:

ConfigurableIPot

public class IPot
extends Pot
implements java.lang.Cloneable, java.util.Observer, RemoteControlled

Describes an IPot, Bernabe Linares Barranco's name for a programamble current source. These are different in their detailed circuit implementation, being based on a Bult&Geelen current splitter whose input current is directly split, insread of being mirrored and then split. I.e., the ones implemented here use a voltage reference for the current splitter that is externally derived instead of coming from the current mirror gate voltage.

In any case, these are integrated on-chip, e.g. on retina test chip testchipARCS and temporal contrast dynamic vision sensor Tmpdiff128, and are programmed over an SPI (serial peripherl interconnect) link from an off-chip microcontroller. This class holds the state of the IPot and describes it.

This class extends Observer so observers can add themselves to be notified when the pot value changes.

Author:

tobi

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.jaer.biasgen.Pot

Pot.Sex, Pot.Type

Field Summary

protected Biasgen	biasgen The enclosing bias generator
protected int	shiftRegisterNumber the position of this ipot in the chain of shift register cells; zero based and starting at the end where the bits are loaded.

Fields inherited from class net.sf.jaer.biasgen.Pot

bitValue, CHANGE_FRACTION, chip, chipNumber, displayPosition, group, log, masterbias, name, numBits, numBytes, pinNumber, prefs, sex, tooltipString, type

Constructor Summary

protected	IPot(Biasgen biasgen) Creates a new instance of IPot passing only the biasgen it belongs to.
	IPot(Biasgen biasgen, java.lang.String name, int shiftRegisterNumber, Pot.Type type, Pot.Sex sex, int bitValue, int displayPosition, java.lang.String tooltipString) Creates a new instance of IPot

Method Summary

void	changeByRatio(float ratio) change ipot current value by ratio
void	decrementCurrent() decrement pot value by ratio
byte[]	getBinaryRepresentation() Computes and returns a the reused array of bytes representing the bias to be sent over hardware interface to the device.
float	getCurrent() Computes the estimated current based on the bit value for the current splitter and the Pot.masterbias
float	getCurrentResolution() return resolution of pot in current.
float	getMaxCurrent()
float	getMinCurrent()
float	getPhysicalValue() returns physical value of bias, e.g.
java.lang.String	getPhysicalValueUnits() return units (e.g.
int	getShiftRegisterNumber() The shift register number is ordered so that the lowest shiftRegisterNumber is the bias at the start of the shift register and must be loaded *last*.
void	incrementCurrent() increment pot value by Pot.CHANGE_FRACTION ratio
javax.swing.JComponent	makeGUIPotControl() Builds the component used to control the IPot.
protected java.lang.String	prefsKey() Returns the String key by which this pot is known in the Preferences.
java.lang.String	processCommand(RemoteControlCommand command, java.lang.String input) Called when remote control recieved for this RemoteControlled.
void	setChipNumber(int chipNumber)
float	setCurrent(float current) sets the bit value based on desired current and Pot.masterbias current.
void	setPhysicalValue(float value) sets physical value of bias
void	setShiftRegisterNumber(int shiftRegisterNumber) The shift register number is ordered so that the lowest shiftRegisterNumber is the bias at the start of the shift register and must be loaded *last*.
java.lang.String	toString()
void	update(java.util.Observable observable, java.lang.Object obj) Responds to updates from Masterbias to notify observers

Methods inherited from class net.sf.jaer.biasgen.Pot

addObserver, decrementBitValue, getBitValue, getChipNumber, getDisplayPosition, getGroup, getMaxBitValue, getMinBitValue, getName, getNumBits, getNumBytes, getPinNumber, getPreferedBitValue, getSex, getTooltipString, getType, incrementBitValue, loadPreferences, preferenceChange, resume, setBitValue, setDisplayPosition, setGroup, setName, setNumBits, setNumBytes, setPinNumber, setSex, setTooltipString, setType, storePreferences, suspend, toBitPatternString

Methods inherited from class java.util.Observable

clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

Methods inherited from class java.lang.Object

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

Field Detail

biasgen

protected Biasgen biasgen

The enclosing bias generator

shiftRegisterNumber

protected int shiftRegisterNumber

the position of this ipot in the chain of shift register cells; zero based and starting at the end where the bits are loaded. The order is very important because the bits for the FIRST bias in the shift register are loaded LAST.

Constructor Detail

IPot

protected IPot(Biasgen biasgen)

Creates a new instance of IPot passing only the biasgen it belongs to. All other parameters take default values.

This IPot also adds itself as an observer for the Masterbias object.

Parameters:

biasgen - the biasgen this ipot is part of

IPot

public IPot(Biasgen biasgen,
            java.lang.String name,
            int shiftRegisterNumber,
            Pot.Type type,
            Pot.Sex sex,
            int bitValue,
            int displayPosition,
            java.lang.String tooltipString)

Creates a new instance of IPot

Parameters:

biasgen - the containing Biasgen.

name - displayed and used to return by name.

shiftRegisterNumber - the position in the shift register, 0 based, starting on end from which bits are loaded. This order determines how the bits are sent to the shift register, lower shiftRegisterNumber are loaded later, so that they end up at the start of the shift register. The last bit on the shift register is loaded first and is the msb of the last bias on the shift register. The last bit loaded into the shift register is the lsb of the first bias on the shift register.

type - (NORMAL, CASCODE) - for user information.

sex - Sex (N, P). User tip.

bitValue - initial bitValue.

displayPosition - position in GUI from top (logical order).

tooltipString - a String to display to user of GUI telling them what the pots does.

Method Detail

toString

public java.lang.String toString()

Overrides:

toString in class Pot

setCurrent

public float setCurrent(float current)

sets the bit value based on desired current and Pot.masterbias current. Observers are notified if value changes.

Parameters:

current - in amps

Returns:

actual float value of current after resolution clipping.

getCurrent

public float getCurrent()

Computes the estimated current based on the bit value for the current splitter and the Pot.masterbias

Returns:

current in amps

setChipNumber

public void setChipNumber(int chipNumber)

getShiftRegisterNumber

public int getShiftRegisterNumber()

The shift register number is ordered so that the lowest shiftRegisterNumber is the bias at the start of the shift register and must be loaded *last*. The highest number should go to the end of the shift register. This bias needs to be loaded first.

Returns:

The shift register number which is ordered so that the lowest shiftRegisterNumber is the bias at the start of the shift register.

setShiftRegisterNumber

public void setShiftRegisterNumber(int shiftRegisterNumber)

The shift register number is ordered so that the lowest shiftRegisterNumber is the bias at the start of the shift register and must be loaded *last*. The highest number should go to the end of the shift register. This bias needs to be loaded first.

Parameters:

shiftRegisterNumber - which lower towards the input side and starts with 0 by convention.

getMaxCurrent

public float getMaxCurrent()

Returns:

max possible current (master current)

getMinCurrent

public float getMinCurrent()

Returns:

min possible current (presently zero, although in reality limited by off-current and substrate leakage).

getCurrentResolution

public float getCurrentResolution()

return resolution of pot in current. This is just Im/2^nbits.

Returns:

smallest possible current change -- in principle

incrementCurrent

public void incrementCurrent()

increment pot value by Pot.CHANGE_FRACTION ratio

decrementCurrent

public void decrementCurrent()

decrement pot value by ratio

changeByRatio

public void changeByRatio(float ratio)

change ipot current value by ratio

Parameters:

ratio - between new current and old value, e.g. 1.1f or 0.9f

update

public void update(java.util.Observable observable,
                   java.lang.Object obj)

Responds to updates from Masterbias to notify observers

Specified by:

update in interface java.util.Observer

Parameters:

observable - ignored

obj - ignored

makeGUIPotControl

public javax.swing.JComponent makeGUIPotControl()

Builds the component used to control the IPot. This component is the user interface.

Specified by:

makeGUIPotControl in class Pot

Returns:

a JComponent that can be added to a GUI

getPhysicalValue

public float getPhysicalValue()

Description copied from class: Pot

returns physical value of bias, e.g. in current amps or voltage volts

Specified by:

getPhysicalValue in class Pot

Returns:

physical value

getPhysicalValueUnits

public java.lang.String getPhysicalValueUnits()

Description copied from class: Pot

return units (e.g. A, mV) of physical value of bias

Specified by:

getPhysicalValueUnits in class Pot

setPhysicalValue

public void setPhysicalValue(float value)

Description copied from class: Pot

sets physical value of bias

Specified by:

setPhysicalValue in class Pot

Parameters:

value - the physical value, e.g. in amps or volts

prefsKey

protected java.lang.String prefsKey()

Returns the String key by which this pot is known in the Preferences. For IPot's, this name is the Chip simple class name followed by IPot., e.g. "Tmpdiff128.IPot.Pr".

Overrides:

prefsKey in class Pot

Returns:

preferences key

getBinaryRepresentation

public byte[] getBinaryRepresentation()

Computes and returns a the reused array of bytes representing the bias to be sent over hardware interface to the device.

Specified by:

getBinaryRepresentation in class Pot

Returns:

array of bytes to be sent, by convention values are ordered in big endian format so that byte 0 is the most significant byte and is sent first to the hardware.

processCommand

public java.lang.String processCommand(RemoteControlCommand command,
                                       java.lang.String input)

Description copied from interface: RemoteControlled

Called when remote control recieved for this RemoteControlled.

Specified by:

processCommand in interface RemoteControlled

Parameters:

command - the received command that was parsed as being the type sent.

input - the input line which starts with the command token.

Returns:

an optional response to the command which can be null.