TMAccess Overview Group

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.


short far pascal TMAccess(

long session_handle,     //session handle for the desired 1-Wire network
void far *state_buffer   // state buffer provided for the 1-Wire network session
);

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

Code Example

See Also

TMRom, TMStrongAccess, TMStrongAlarmAccess, TMOverAccess