Component: Lookup tables (Storage)

Author	Matrix Ltd
Version	1.7
Category	Storage

Lookup tables component

A lookup-table component allowing an easy way to place arrays of static data into ROM memory. The LUT data is accessed directly allowing very low overhead when collecting the data.

Detailed description

No detailed description exists yet for this component

Examples

A look up table component is useful when including data into a program which may not be linear and therefore hard to calculate.

One example of this is a sine wave or working out a temperature based on the resistance of a thermistor.

For a simple example lets say we want to store a sine wave on board the microcontroller.

First of all we use Excel to generate the data for a sine wave to do this we work out the angles in degrees we want to reproduce, then convert the degrees to radians and then generate the Sine wave for the angle. the angle returned will be between -1 and 1 so we need to convert this to fit into the microcontroller's memory. The most efficient way is to store the value as a byte which means scaling up the output to 0 - 255 and removing the real portion of the number to give integer values.

File:SineWaveLUT.xlsx

Then using the file -> Save as menu in Excel we can export the data as a raw .CSV file.

File:SineWaveLUT.csv

The line in the CSV file we are interested in is the Integer Offset Data. We can then copy and paste this data into the integer property of the look up table component.

In this example Flowcode file we display the LUT data onto a graphical LCD display LUT Here is what you should expect to see on the glcd after running the simulation.

Downloadable macro reference

	GetFloats
Gets the float LUT
[[File:]] -	Dest
- VOID	Return

	GenerateCache
Generates the C code for the arrays so it does not need to be done at compile time
- VOID	Return

	GetIntCount
Gets the number of int LUT entries
- UINT	Return

	ClearInts
Clear all int LUT values
- VOID	Return

	GetFloatCount
Gets the number of float LUT entries
- UINT	Return

	GetIntBits
Gets the number of bits-per-int in the LUT
- BYTE	Return

	SetIntBits
Sets the size of an int LUT entry
- BYTE	Bits
- VOID	Return

	GetFloatBits
Gets the number of bits-per-float in the LUT
- BYTE	Return

	ClearFloats
Clear all float LUT values
- VOID	Return

	GetFloat
Gets a float from the LUT
- ULONG	Index
[[File:]] -	Return

	GetInts
Gets the int LUT
- ULONG	Dest
- VOID	Return

	GetLUTCount
Gets the number of individual data entries stored in the LUT.
- UINT	Return

	GetInt
Gets an integer from the LUT
- ULONG	Index
- ULONG	Return

	SetFloatBits
Sets the size of a float LUT entry
- BYTE	Bits
- VOID	Return

	AddInt
Int to add to the int array
- ULONG	Value
Int to add to the int array
- VOID	Return

	AddFloat
Add a float to the floating point LUT
[[File:]] -	Value
Floating point values
- VOID	Return

	Initialise
Sets up the GSM module. Returns 0 for OK, 255 for no reply and 254 for command fail.
- BYTE	Return

	SampleAccel
Samples the accelerometer 0 = no new data, 1 = new data available
- BYTE	Return

	Left
Rotates the robot left - waits for the angle to be traversed before returning
- UINT	Angle
Angle to turn in degrees
- VOID	Return

	ReadIR
Reads an IR sensor 0=Left, 1=FrontLeft, 2=Front, 3=FrontRight, 4=Right, 5=RearRight, 6=Rear, 7=RearLeft
- BYTE	index
0=Left, 1=FrontLeft, 2=Front, 3=FrontRight, 4=Right, 5=RearRight, 6=Rear, 7=RearLeft
- UINT	Return

	LCDDrawPixel
Allows a single pixel on the LCD to be set or cleared
- BYTE	X
X Pixel 0-127
- BYTE	Y
Y Pixel 0-31
- BYTE	State
0=White (Off), 1=Black (On)
- VOID	Return

	ServoSetPosition
Allows one of the servo positions to be assigned
- BYTE	Channel
Range 0-3
- BYTE	Position
Range 0-255
- VOID	Return

	CardBitmap
Displays a monochrome bitmap read from the card on the LCD
- BYTE	X
Range 0-127
- BYTE	Y
Range 0-31
- STRING	Filename
- BYTE	Return

	CardRecordMic
Records an audio stream on the card from the microphone
- BYTE	BitDepth
0=8-bit, 1=16-bit
- BYTE	SampleRate
Sample Rate 0=8KHz, 1=16KHz
- UINT	RecordTime
Time to record for in seconds, Range 0-65535
- STRING	Filename
- BYTE	Return

	CardOpen
Attempts to open an existing file on the SD card 255=Error, 1=File not found, 0=Open OK
- STRING	Filename
- BYTE	Return

	Forwards
Drives the robot forwards - waits for the distance to be traversed before returning
- UINT	Distance
Distance in mm
- VOID	Return

	ReadBearing
Reads the compass bearing based on the degrees clockwise from magnetic north.
[[File:]] -	Return

	GetConsoleHandle
Gets the handle to the console allowing data displaying on the panel etc.
[[File:]] -	Return

	LCDDrawLine
Allows a single pixel width line to be drawn on the LCD
- BYTE	X1
X Pixel 0-127
- BYTE	Y1
Y Pixel 0-31
- BYTE	X2
X Pixel 0-127
- BYTE	Y2
Y Pixel 0-31
- VOID	Return

	ServoAutoMoveToPosition
Allows one of the servo positions to move gradually to a new position
- BYTE	Channel
Range 0-3
- BYTE	Position
Range 0-255
- VOID	Return

	ReadAllValue
Reads a single value stored from the read all command Index dictates which sensor value to read
- BYTE	Index
0=SW, 1-8=IR, 9-10=Line, 11=Light, 12=Mic, 13-15=Accel
- UINT	Return

	LCDBacklight
Allows the LCD backlight brighntess to be adjusted
- BYTE	Intensity
Range 0-100, 0=Off, 1=Min Brightness, 100=Max Brightness
- VOID	Return

	LCDDrawRect
Allows a rectangle to be drawn on the LCD
- BYTE	X1
X Pixel 0-127
- BYTE	Y1
Y Pixel 0-31
- BYTE	X2
X Pixel 0-127
- BYTE	Y2
Y Pixel 0-31
- VOID	Return

	ReadLine
Reads one of the IR line sensors 0-1 0=Left, 1=Right
- BYTE	index
0=Left, 1=Right
- UINT	Return

	ServoDisable
Allows one of the servo outputs 0-3 to be disabled
- BYTE	Channel
Range 0-3
- VOID	Return

	ServoEnable
Allows one of the servo outputs 0-3 to be enabled
- BYTE	Channel
Range 0-3
- VOID	Return

	CardReadByte
Reads a byte from the currently open file. Starts at the beginning of the file and auto increments to the end
- BYTE	Return

	CardErase
Attempts to delete an existing file on the SD card 255=Error, 1=File not found, 0=Delete OK
- STRING	Filename
- BYTE	Return

	CardWriteByte
Appends a byte to the end of the currently open file
- BYTE	Data
- VOID	Return

	EncoderRead
Reads one of the motor encoder counters. Approx 0.328296mm of travel per encoder unit.
- BYTE	index
0=Left, 1=Right
- UINT	Return

	SetMotors
Sets the motor speeds without feedback Range -100 to 100
[[File:]] -	Left
Range -100 to 100
[[File:]] -	Right
Range -100 to 100
- VOID	Return

	Backwards
Drives the robot backwards - waits for the distance to be traversed before returning
- UINT	Distance
Distance in mm
- VOID	Return

	EncoderReset
Resets the motor encoder counters
- VOID	Return

	LCDVerbose
Allows the LCD to automatically report the API commands as they get processed. Default - verbose on
- BYTE	State
0=Off 1=On
- VOID	Return

	SetProp
Allows the COM port property to be set from a parent component.
- STRING	PropName
- ULONG	PropVal
- VOID	Return

	CardInit
Attempts to startup the SD card 255=No Card, 254=Init Fail, 0=Init OK
- BYTE	Return

	GetProp
Allows the property filter for the COM port list to be copied to a parent component.
- STRING	PropName
- STRING	Return

	LCDClear
Clears the LCD
- VOID	Return

Property reference

	Properties
	Storage Type
Controls the data type stored by the component.
	Storage Sign
Controls if the integer numbers are allowed to be negative. Unsigned = Numbers are positive only. Signed = Numbers can be positive and negative.
	Integers
Comma seperated integer data which is used to create the C code which is inserted into the ROM.
	Num Values
	Embed Into C
Flag to decide if code should be generated to C or not If this is false then the LUT is simulation only
	Connections
	Simulations