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Микроконтроллеры ЭВМ

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BASCOM AVR, help reference (2007).PDF

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for the frame space
Dim V As Byte , B1 As Byte
Dim C As Integer , D As Byte
Dim S As String * 15
Input "Use this to ask a question " , V	'leave out for no
Input B1	'leave out for no
question
Input "Enter integer " , C
Print C
Inputhex "Enter hex number (4 bytes) " , C
Print C
Inputhex "Enter hex byte (2 bytes) " , D
Print D
Input "More variables " , C , D
Print C ; " " ; D
Input C Noecho	'supress echo
Input "Enter your name " , S
Print "Hello " ; S
Input S Noecho	'without echo
Print S
End

ELSE

Action

Executed if the IF-THEN expression is false.

Syntax

ELSE

Remarks

You don't have to use the ELSE statement in an IF THEN .. END IF structure. You can use the ELSEIF statement to test for another condition.

IF a = 1 THEN

...

ELSEIF a = 2 THEN

ELSEIF b1 > a THEN

...

ELSE

...

END IF

ENABLE

Action

Enable specified interrupt.

Syntax

ENABLE interrupt

Remarks

Interrupt	Description
INT0	External Interrupt 0
INT1	External Interrupt 1
OVF0,TIMER0,	TIMER0 overflow interrupt
COUNTER0
OVF1,TIMER1,	TIMER1 overflow interrupt
COUNTER1
CAPTURE1, ICP1	INPUT CAPTURE TIMER1 interrupt
COMPARE1A,OC1A or	TIMER1 OUTPUT COMPARE A interrupt
COMPARE1, OC1	In case of only one compare interrupt
COMPARE1B,OC1B	TIMER1 OUTPUT COMPARE B interrupt
SPI	SPI interrupt
URXC	Serial RX complete interrupt
UDRE	Serial data register empty interrupt
UTXC	Serial TX complete interrupt
SERIAL	Disables URXC, UDRE and UTXC
ACI	Analog comparator interrupt
ADC	A/D converter interrupt

By default all interrupts are disabled.

To enable the enabling and disabling of interrupts use ENABLE INTERRUPTS.

Other chips might have additional interrupt sources such as INT2, INT3 etc.

Var = ENCODER( pin1, pin2, LeftLabel, RightLabel , wait)

Remarks

Var	The target variable that is assigned with the result
Pin1 and pin2	These are the names of the PIN registers to which the output of the
	encoder is connected. Both pins must be on the same PIN register. So
	Pinb.0 and Pinb.7 is valid while PinB.0 and PinA.0 is not.
LeftLabel	The name of the label that will be called/executed when a transition
	to the left is encoded.
RightLabel	The name of the label that will be called/executed when a transition
	to the right is encountered.
wait	A value of 0 will only check for a rotation/pulse. While a value of 1
	will wait until a user actual turns the encoder. A value of 1 will thus
	halt your program.

There are some conditions you need to fulfill :

The label that is called by the encoder must be terminated by a RETURN statement.

The pin must work in the input mode. By default all pins work in input mode.

The pull up resistors must be activated by writing a logic 1 to the port registers as the examples shows.

Rotary encoders come in many flavors. Some encoders also have a build in switch.

A sample of an encoder

page -479-

Since the microprocessor has internal pull up resistors, you do not need externalpull up resistors for most encoders.

Example

'-----------------------------------------------------------------------------
------------	: encoder.bas
'name	: encoder.bas
'copyright	: (c) 1995-2005, MCS Electronics
'purpose	: demonstration of encoder function
'micro	: Mega128
'suited for demo	: yes
'commercial addon needed	: no
'An encoder has 2 outputs	and a ground

'We connect the outputs to pinb.0 and pinb.1

'You may choose different pins as long as they are at the same PORT 'The pins must be configured to work as input pins

'This function works for all PIN registers '-----------------------------------------------------------------------------

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

$regfile = "m128def.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

Print "Encoder test"

Dim B As Byte

'we have dimmed a byte because we need to maintain the state of the encoder

Portb = &B11				' activate pull up
registers
Do
B = Encoder(pinb.0 , Pinb.1 , Links , Rechts , 1)				1 means wait for
'			^---	1 means wait for
change which blocks programflow			^	labels which are
'		^--------	^	labels which are
called	^	^		port PINs
'	^	^		port PINs
Print B
Waitms 10
Loop
End

'so while you can choose PINB0 and PINB7,they must be both member of PINB 'this works on all PIN registers

Links:

Print "left rotation"

Return

Rechts:

Print "right rotation"

Return

page -480-

End

END

Action

Terminate program execution.

Syntax

END

Remarks

STOP can also be used to terminate a program.

When an END statement is encountered, all interrupts are disabled and a never-ending loop is generated.

When a STOP is encountered the interrupts will not be disabled. Only a never ending loop will be created.

In an embedded application you probably do not want to end the application. But there are cases where you do want to end the application. For example when you controlsome motors, and you determine a failure, you do not want to use a Watchdog reset because then the failure will occur again. In that case you want to display an error, and wait for service personal to fix the failure.

It is important to notice that without the END statement, your programcan behave strange in certain cases. For example :

Print "Hello"

Note that there is no END statement. So what will happen? The program will print "Hello". But as the compiler places the library code behind the program code, the micro will execute the library code ! But without being called. As most library code are assembler sub routines that end with a RET, your program will most likely crash, or reset and repeat for ever.

$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 A As Byte , B1 As Byte
Input "Number " , A	'ask for number
If A = 1 Then	'test number
Print "You got it!"
End If
If A = 0 Then	'test again
Print "Wrong"	'thats wrong
Else	'print this if a
is not 0
Print "Almost?"
End If
Rem You Can Nest If Then Statements Like This
B1 = 0
If A = 1 Then
If B1 = 0 Then
Print "B1=0"
End If
Else
Print "A is not 0"
End If
Input "Number " , A	'
If A = 1 Then	'
Print "Ok"	'use elseif for
Elseif A = 2 Then	'use elseif for
more tests
Print "2" : A = 3
Elseif A = 3 Then
Print "3"
End If
If A.1 = 1 Then Print "Bit 1 set"	'test for a bit
End

Enable Interrupts	'allow interrupts to be set
Enable Timer1	'enables the TIMER1 interrupt

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

Print "Hello"	'print this
End	'end program execution and disable all interrupts