TMOverAccess Overview Group

The TMOverAccess API call transmits a TMTouchReset signal and returns 0 if no Presence signal is detected. If a Presence signal is detected, it sends an Overdrive match to the device whose ROM code is in the internal eight byte buffer. The Overdrive match readies the 1-Wire device to accept memory function commands such as read scratchpad and also sets the device in Overdrive speed. 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, in Overdrive communication mode, and ready for a device specific command.

short far pascal TMOverAccess(

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.



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.


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, in Overdrive mode, and ROM selected

<0 => TMEX Network Error Return Code

Code Example

See Also

TMRom; TMStrongAccess, TMStrongAlarmAccess; TMAccess