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Микроконтроллеры ЭВМ

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BASCOM AVR, help reference (2007).PDF

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Action

Returns the index of a series of data.

Syntax

var = LOOKDOWN( value, label, entries)

Remarks

Var	The returned index value
Value	The value to search for
Label	The label where the data starts
entries	The number of entries that must be searched

When you want to look in BYTE series the VALUE variable must be dimensioned as a BYTE. When you want to look in INTEGER or WORD series the VALUE variable must be dimensioned as an INTEGER.

The LookDown function is the counterpart of the LookUp function.

Lookdown will search the data for a value and will return the index when the value is found. It will return –1 when the data is not found.

See also

LOOKUPSTR , LOOKUP

Example

'-----------------------------------------------------------------------------
------------	: lookdown.bas
'name	: lookdown.bas
'copyright	: (c) 1995-2005, MCS Electronics
'purpose	: demo : LOOKDOWN
'micro	: Mega48
'suited for demo	: yes
'commercial addon needed	: no

'-----------------------------------------------------------------------------

------------

$regfile = "m48def.dat"	' specify the used
micro	' used crystal
$crystal = 4000000	' used crystal
frequency	' use baud rate
$baud = 19200	' use baud rate
$hwstack = 32	' default use 32
for the hardware stack	' default use 10
$swstack = 10	' default use 10
for the SW stack	' default use 40
$framesize = 40	' default use 40
for the frame space
Dim Idx As Integer , Search As Byte , Entries As Byte
'we want to search for the value 3
Search = 3
'there are 5 entries in the table
Entries = 5

page -563-

'lookup and return the index

Idx = Lookdown(search , Label , Entries)

Print Idx

Search = 1

Idx = Lookdown(search , Label , Entries)

Print Idx

Search = 100
Idx = Lookdown(search , Label , Entries)	' return -1 if not
Print Idx	' return -1 if not
found
'looking for integer or word data requires that the search variable is
'of the type integer !
Dim Isearch As Integer
Isearch = 400
Idx = Lookdown(isearch , Label2 , Entries)	' return 3
Print Idx	' return 3

End

Label:

Data 1 , 2 , 3 , 4 , 5

Label2:

Data 1000% , 200% , 400% , 300%

LOOKUP

Action

Returns a value from a table.

Syntax

var = LOOKUP( value, label)

Remarks

Var	The returned value
Value	A value with the index of the table
Label	The label where the data starts

The value can be up to 65535. 0 will return the first entry.

See also

LOOKUPSTR

Example

$regfile = "m48def.dat" ' specify the used

page -564-

© MCS Electronics, 1995-2007
micro	' used crystal
$crystal = 4000000	' used crystal
frequency	' use baud rate
$baud = 19200	' use baud rate
$hwstack = 32	' default use 32
for the hardware stack	' default use 10
$swstack = 10	' default use 10
for the SW stack	' default use 40
$framesize = 40	' default use 40
for the frame space
Dim B1 As Byte , I As Integer
B1 = Lookup(2 , Dta)	' Prints 3 (zero
Print B1	' Prints 3 (zero
based)
I = Lookup(0 , Dta2)	' print 1000
Print I
End
Dta:
Data 1 , 2 , 3 , 4 , 5
Dta2:
Data 1000% , 2000%

LOOKUPSTR

Action

Returns a string from a table.

Syntax

var = LOOKUPSTR( value, label )

Remarks

Var	The string returned
Value	A value with the index of the table. The index is zero-based. That is, 0 will
	return the first element of the table.
Label	The label where the data starts

The index value can have a maximum value of 255.

See also

LOOKUP , LOOKDOWN

Example

$regfile = "m48def.dat"	' specify the used
micro	' used crystal
$crystal = 4000000	' used crystal
frequency	' use baud rate
$baud = 19200	' use baud rate
$hwstack = 32	' default use 32
	page -565-

© MCS Electronics, 1995-2007
for the hardware stack	' default use 10
$swstack = 10	' default use 10
for the SW stack	' default use 40
$framesize = 40	' default use 40
for the frame space
Dim S As String * 4 , Idx As Byte
Idx = 0 : S = Lookupstr(idx , Sdata)	'will print 'This'
Print S	'will print 'This'
End
Sdata:
Data "This" , "is" , "a test"

LOW

Action

Retrieves the least significant byte of a variable.

Syntax

var = LOW( s )

Remarks

Var	The variable that is assigned with the LSB of var S.
S	The source variable to get the LSB from.

You can also assign a byte to retrieve the LSB of a Word or Long.

For example :

B = L , where B is a byte and L is a Long.

See also

HIGH , HIGHW

Example

$regfile = "m48def.dat"	' specify the used
micro	' used crystal
$crystal = 4000000	' used crystal
frequency	' use baud rate
$baud = 19200	' use baud rate
$hwstack = 32	' default use 32
for the hardware stack	' default use 10
$swstack = 10	' default use 10
for the SW stack	' default use 40
$framesize = 40	' default use 40
for the frame space
Dim I As Integer , Z As Byte
I = &H1001	' is 1
Z = Low(i)	' is 1
End

page -566-

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