OWRESET Pin {, ByteVar}

Function
Generates a 1-Wire reset sequence on Pin, returning (optional) status information in ByteVar.

• Pin  is any SX I/O pin (RA.0 .. RA.7, RB.0 .. RB.7, RC.0 .. RC.7, RD.0 .. RD.7, RE.0 .. RE.7).
• ByteVar  is an optional byte variable that will hold the status of the 1-Wire connections (see below).

Quick Facts

	All SX Models
Special Notes	The DQ pin (specified by Pin) must have a 4.7 kΩ pull-up resister.
	1-Wire commands require a FREQ setting of 4 MHz or higher.
Status value	0 = Bus shorted to Vss; 1 = Bad connection; 2 = Good connection; 3 = No device

Explanation
All transactions on the 1-Wire bus begin with an Initialization sequence that consists of a Reset pulse generated by the master, followed by a Presence pulse generated by the 1-Wire slave. The OWRESET instruction generates the 1-Wire Reset pulse on the specified DQ Pin and, if ByteVar is specified, will monitor the bus and return status information to the program.

The diagram and table below details the Reset pulse generated by the SX with OWRESET and a typical Presence pulse generated by a 1-Wire slave, in response.

Note	Timing	Description
A	~ 480 µS	1-Wire Reset pulse (SX master)
B	~ 15 µS	Delay before sampling for bus short
C	~ 70 µS	Delay before sampling for Presence
D	~ 60 - 240 µS	Presence pulse (1-Wire slave)
E	~ 480 µS	Reset recovery

Related instructions: OWRDBIT, OWRDBYTE, OWWRBIT, and OWWRBYTE