© MCS Electronics, 1995-2007
'we need a loop counter and a word/integer for counting the ID's on the bus
Dim I As Byte , W As Word
'Now search for the first device on the bus Reg_no(1) = 1wsearchfirst()
For I = 1 To 8 |
'print the number |
Print Hex(reg_no(i)); |
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Next |
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Do |
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'Now search for other devices |
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Reg_no(1) = 1wsearchnext() |
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For I = 1 To 8 |
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Print Hex(reg_no(i)); |
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Next |
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Loop Until Err = 1 |
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'When ERR = 1 is returned it means that no device is found anymore 'You could also count the number of devices
W = 1wirecount()
'It is IMPORTANT that the 1wirecount function returns a word/integer 'So the result variable must be of the type word or integer
'But you may assign it to a byte or long too of course
Print W
'as a bonus the next routine :
'first fill the array with an existing number Reg_no(1) = 1wsearchfirst()
'unremark next line to chance a byte to test the ERR flag 'Reg_no(1) = 2
'now verify if the number exists 1wverify Reg_no(1)
Print Err
'err =1 when the ID passed n reg_no() does NOT exist
'optinal call it with pinnumber line 1wverify reg_no(1),pinb,1
'As for the other 1wire statements/functions, you can provide the port and pin number as anoption
'W = 1wirecount(pinb , 1) 'for example look at pin PINB.1
End
1WRESET
Action
This statement brings the 1wire pin to the correct state, and sends a reset to the bus.
Syntax
1WRESET
1WRESET , PORT , PIN
page -256-
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© MCS Electronics, 1995-2007 |
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Remarks |
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1WRESET |
Reset the 1WIRE bus. The error variable ERR will return 1 if an error |
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occurred |
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Port |
The register name of the input port. Like PINB, PIND. |
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Pin |
The pin number to use. In the range from 0-7. May be a numeric constant |
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or variable. |
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The global variable ERR is set when an error occurs.
There is also support for multi 1-wire devices on different pins.
To use this you must specify the port and pin that is used for the communication.
The 1wreset, 1wwrite and 1wread statements will work together when used with the old syntax. And the pin can be configured from the compiler options or with the CONFIG 1WIRE statement.
The syntax for additional 1-wire devices is :
1WRESET port , pin
1WWRITE var/constant ,bytes] , port, pin
var = 1WREAD( bytes) , for the configured 1 wire pin
var = 1WREAD(bytes, port, pin) ,for reading multiple bytes
See also
1WREAD , 1WWRITE
Example
'----------------------------------------------------------------------------- |
|
--- |
: 1wire.bas |
'name |
|
'copyright |
: (c) 1995-2005, MCS Electronics |
'purpose |
: demonstrates 1wreset, 1wwrite and 1wread() |
'micro |
: Mega48 |
'suited for demo |
: yes |
'commercial addon needed |
: no |
' pull-up of 4K7 required to VCC from Portb.2 |
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' DS2401 serial button connected to Portb.2 |
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'----------------------------------------------------------------------------- |
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--- |
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$regfile = "m48def.dat" |
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$crystal = 4000000 |
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$hwstack = 32 |
' default use 32 |
for the hardware stack |
'default use 10 |
$swstack = 10 |
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for the SW stack |
'default use 40 |
$framesize = 40 |
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for the frame space |
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'when only bytes are used, use the following lib for smaller code |
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$lib "mcsbyte.lib" |
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Config 1wire = Portb.0 |
'use this pin |
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page -257- |
© MCS Electronics, 1995-2007 |
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'On the STK200 jumper B.0 must be inserted |
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Dim Ar(8) As Byte , A As Byte , I As Byte |
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Do |
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Wait 1 |
'reset the device |
1wreset |
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Print Err |
'print error 1 if |
error |
'read ROM command |
1wwrite &H33 |
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For I = 1 To 8 |
'place into array |
Ar(i) = 1wread() |
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Next |
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'You could also read 8 bytes a time by unremarking the next line |
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'and by deleting the for next above |
'read 8 bytes |
'Ar(1) = 1wread(8) |
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For I = 1 To 8 |
'print output |
Print Hex(ar(i)); |
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Next |
'linefeed |
Loop |
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'NOTE THAT WHEN YOU COMPILE THIS SAMPLE THE CODE WILL RUN TO THIS POINT 'THIS because of the DO LOOP that is never terminated!!!
'New is the possibility to use more than one 1 wire bus |
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'The following syntax must be used: |
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For I = 1 To 8 |
'clear array to |
Ar(i) = 0 |
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see that it works |
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Next |
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1wreset Pinb , 2 |
'use this port and |
pin for the second device |
'note that now the |
1wwrite &H33 , 1 , Pinb , 2 |
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number of bytes must be specified! |
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'1wwrite Ar(1) , 5,pinb,2 |
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'reading is also different |
'read 8 bytes from |
Ar(1) = 1wread(8 , Pinb , 2) |
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portB on pin 2 |
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For I = 1 To 8 |
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Print Hex(ar(i)); |
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Next |
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'you could create a loop with a variable for the bit number !
For I = 0 To 3 'for pin 0-3 1wreset Pinb , I
1wwrite &H33 , 1 , Pinb , I Ar(1) = 1wread(8 , Pinb , I)
For A = 1 To 8 Print Hex(ar(a));
Next
Print Next
End
page -258-
© MCS Electronics, 1995-2007
1WREAD
Action
This statement reads data from the 1wire bus into a variable.
Syntax
var2 = 1WREAD( [ bytes] )
var2 = 1WREAD( bytes , port , pin)
Remarks
var2 |
Reads a byte from the bus and places it into variable var2. |
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Optional the number of bytes to read can be specified. |
Port |
The PIN port name like PINB or PIND. |
Pin |
The pin number of the port. In the range from 0-7. Maybe a numeric |
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constant or variable. |
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|
Multi 1-wire devices on different pins are supported.
To use this you must specify the port pin that is used for the communication.
The 1wreset, 1wwrite and 1wread statements will work together when used with the old syntax. And the pin can be configured from the compiler options or with the CONFIG 1WIRE statement.
The syntax for additional 1-wire devices is : 1WRESET port, pin
1WWRITE var/constant , bytes, port, pin
var = 1WREAD(bytes, port, pin) for reading multiple bytes
See also
1WWRITE , 1WRESET
Example
'----------------------------------------------------------------------------- |
|
--- |
: 1wire.bas |
'name |
|
'copyright |
: (c) 1995-2005, MCS Electronics |
'purpose |
: demonstrates 1wreset, 1wwrite and 1wread() |
'micro |
: Mega48 |
'suited for demo |
: yes |
'commercial addon needed |
: no |
' pull-up of 4K7 required to VCC from Portb.2 ' DS2401 serial button connected to Portb.2
'-----------------------------------------------------------------------------
---
$regfile = "m48def.dat" $crystal = 4000000
page -259-
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© MCS Electronics, 1995-2007 |
$hwstack = 32 |
' default use 32 |
for the hardware stack |
'default use 10 |
$swstack = 10 |
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for the SW stack |
'default use 40 |
$framesize = 40 |
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for the frame space |
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'when only bytes are used, use the following lib for smaller code $lib "mcsbyte.lib"
Config 1wire = Portb.0 |
'use this pin |
'On the STK200 jumper B.0 must be inserted |
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Dim Ar(8) As Byte , A As Byte , I As Byte |
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Do |
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Wait 1 |
'reset the device |
1wreset |
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Print Err |
'print error 1 if |
error |
'read ROM command |
1wwrite &H33 |
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For I = 1 To 8 |
'place into array |
Ar(i) = 1wread() |
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Next |
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'You could also read 8 bytes a time by unremarking the next line |
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'and by deleting the for next above |
'read 8 bytes |
'Ar(1) = 1wread(8) |
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For I = 1 To 8 |
'print output |
Print Hex(ar(i)); |
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Next |
'linefeed |
Loop |
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'NOTE THAT WHEN YOU COMPILE THIS SAMPLE THE CODE WILL RUN TO THIS POINT 'THIS because of the DO LOOP that is never terminated!!!
'New is the possibility to use more than one 1 wire bus |
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'The following syntax must be used: |
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For I = 1 To 8 |
'clear array to |
Ar(i) = 0 |
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see that it works |
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Next |
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1wreset Pinb , 2 |
'use this port and |
pin for the second device |
'note that now the |
1wwrite &H33 , 1 , Pinb , 2 |
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number of bytes must be specified! |
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'1wwrite Ar(1) , 5,pinb,2 |
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'reading is also different |
'read 8 bytes from |
Ar(1) = 1wread(8 , Pinb , 2) |
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portB on pin 2 |
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For I = 1 To 8 |
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Print Hex(ar(i)); |
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Next |
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'you could create a loop with a variable for the bit number !
For I = 0 To 3 'for pin 0-3 1wreset Pinb , I
1wwrite &H33 , 1 , Pinb , I
page -260-