
One-Wire Master Registers
1511
SLAU723A – October 2017 – Revised October 2018
Copyright © 2017–2018, Texas Instruments Incorporated
1-Wire Master Module
22.5.1 ONEWIRECS Register (Offset = 0x0) [reset = 0x0]
1-Wire Control and Status (ONEWIRECS), offset 0x000
The 1-Wire Control and Status (ONEWIRECS) register contains the control and status bits for the 1-Wire
bus, including active state and passive detection. The OP field is written to start an operation. If executing
a write or a write/read, the Bn field of the 1-Wire Data Write (ONEWIREDATW) register must be written
first before programming the OP field.
ONEWIRECS is shown in
and described in
Return to
Figure 22-7. ONEWIRECS Register
31
30
29
28
27
26
25
24
USEALT
ALTP
RESERVED
R/W-0x0
R/W-0x0
R-0x0
23
22
21
20
19
18
17
16
RESERVED
BSIZE
R-0x0
R/W-0x0
15
14
13
12
11
10
9
8
RESERVED
STUCK
NOATR
BUSY
R-0x0
R-0x0
R-0x0
R-0x0
7
6
5
4
3
2
1
0
SKATR
LSAM
ODRV
SZ
OP
RST
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
R/W-0x0
Table 22-5. ONEWIRECS Register Field Descriptions
Bit
Field
Type
Reset
Description
31
USEALT
R/W
0x0
Two Wire Enable.
0x0 = Function in standard 1-Wire mode, using only the OWIRE
signal for both input and output.
0x1 = Use the OWIRE signal for the input and the OWALT signal for
the output.
30
ALTP
R/W
0x0
Alternate Polarity Enable.
0x0 = Output pin is driven low to drive 1-wire line low.
0x1 = Output pin is driven high to drive 1-Wire line low (that is, the
output pin is connected to an NFET).
29-19
RESERVED
R
0x0
18-16
BSIZE
R/W
0x0
Last Byte Size. This field indicates the bit-size of the last byte. These
bits are sent and received least significant bit first.
0x0 = 8 bits (1 byte)
0x1 = 1 bit
0x2 = 2 bits
0x3 = 3 bits
0x4 = 4 bits
0x5 = 5 bits
0x6 = 6 bits
0x7 = 7 bits
15-11
RESERVED
R
0x0
10
STUCK
R
0x0
STUCK Status.
0x0 = STUCK status is not detected.
0x1 = Indicates line is being held low (other than in normal
operation). The STUCK bit in the ONEWIRERIS is asserted when a
line-hold-low error is detected.