The TMAccess API call transmits a TMTouchReset signal and returns
0 if no Presence signal is detected. If a Presence signal is detected, it
accesses the device whose ROM code is in the internal eight byte buffer. The
access readies the 1-Wire device to accept memory function commands such as
read scratchpad. Note that a successful return of 1 from TMAccess does not
guarantee that the device whose serial ROM number is in the internal eight
byte buffer is actually on the 1-Wire network. A successful return only
guarantees that some 1-Wire device is on the 1-Wire network and if the desired
1-Wire device is present then it is selected and ready for a device specific
command.
For a description of the above types, see the TMEX Type Descriptions.
Parameters
session_handle
Specifies the session handle returned from the API function TMExtendedStartSession that specifies the desired 1-Wire network port. This parameter is required by most TMEX API functions.
state_buffer
Specifies a pointer to a memory location that TMEX keeps all of the state information for the 1-Wire networks. This parameter is required by most TMEX API functions.
Return Value
0 => no presence on 1-Wire network
1 => presence on 1-Wire network and ROM selected
<0 => TMEX Network Error Return Code
See Also
TMRom, TMStrongAccess, TMStrongAlarmAccess, TMOverAccess