© MCS Electronics, 1995-2007

Ar(1) = 1wread(8 , Pinb , I)

For A = 1 To 8

Print Hex(ar(a));

Next

Print

Next

End

1WSEARCHFIRST

Action

This statement reads the first ID from the 1wire bus into a variable(array).

Syntax

var2 = 1WSEARCHFIRST()

var2 = 1WSEARCHFIRST( port , pin)

Remarks

The 1wireSearchFirst() function must be called once to initiate the ID retrieval process. After the 1wireSearchFirst() function is used you should use successive function calls to the 1wSearchNext function to retrieve other ID's on the bus.

A string can not be assigned to get the values from the bus. This because a nul may be returned as a value and the nul is also used as a string terminator.

I would advice to use a byte array as shown in the example.

The 1wirecount function will take 4 bytes of SRAM.

___1w_bitstorage , Byte used for bit storage : lastdeviceflag bit 0

id_bit bit 1 cmp_id_bit bit 2 search_dir bit 3

___1wid_bit_number, Byte

___1wlast_zero, Byte

___1wlast_discrepancy , Byte

ASM

The following asm routines are called from mcs.lib.

_1wire_Search_First : (calls _1WIRE, _ADJUST_PIN , _ADJUST_BIT_ADDRESS) Parameters passed : R24 : pin number, R30 : port , X : address of target array Returns nothing.

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© MCS Electronics, 1995-2007

See also

1WWRITE , 1WRESET , 1WREAD , 1WSEARCHNEXT, 1WIRECOUNT

Example

'The following internal bytes are used by the scan routines '___1w_bitstorage , Byte used for bit storage :

'lastdeviceflag bit 0

'___1wid_bit_number, Byte '___1wlast_zero, Byte '___1wlast_discrepancy , Byte '___1wire_data , string * 7 (8 bytes)

'[DIM variables used]

'we need some space from at least 8 bytes to store the ID

Dim Reg_no(8) As Byte

'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()

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Next

Print

Loop Until Err = 1

'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

1WSEARCHNEXT

Action

This statement reads the next ID from the 1wire bus into a variable(array).

Syntax

var2 = 1WSEARCHNEXT()

var2 = 1WSEARCHNEXT( port , pin)

Remarks

The 1wireSearchFirst() function must be called once to initiate the ID retrieval process. After the 1wireSearchFirst() function is used you should use successive function calls to the 1wireSearchNext function to retrieve other ID's on the bus.

A string can not be assigned to get the values from the bus. This because a nul may be returned as a value and the nul is also used as a string terminator.

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