Datasheet

14Maxim Integrated
DS2483
Single-Channel 1-Wire Master
with Adjustable Timing and Sleep Mode
1-Wire Reset
Figure 4. 1-Wire Reset/Presence-Detect Cycle
Command Code
B4h
Command Parameter
None
Description
Generates a 1-Wire reset/presence-detect cycle at the 1-Wire line (Figure 4). The state of
the 1-Wire line is sampled at t
SI
and t
MSP
and the result is reported to the host processor
through the Status register bits PPD and SD.
Typical Use
To initiate or end any 1-Wire communication sequence.
Restriction
1-Wire activity must have ended before the DS2483 can process this command. Strong
pullup (see the SPU bit) should not be used in conjunction with the 1-Wire Reset command.
If SPU is enabled, the PPD bit may not be valid and may cause a violation of the device’s
absolute maximum rating.
Error Response
Command code is not acknowledged if 1WB = 1 at the time the command code is received
and the command is ignored.
Command Duration
2 O t
RSTL
+ maximum 262.5ns, counted from the falling SCL edge of the command code
acknowledge bit.
1-Wire Activity
Begins maximum 262.5ns after the falling SCL edge of the command code acknowledge bit.
Read Pointer Position
Status register (for busy polling).
Status Bits Affected
1WB (set to 1 for 2 O t
RSTL
), PPD is updated at t
RSTL
+ t
MSP
, SD is updated at t
RSTL
+ t
SI
.
Device Configurations Affected
1WS, APU, SPU apply.
Port Configurations Affected
t
RSTL
, t
MSP
, t
W0L
, t
REC0
, and R
WPU
current values apply.
PULLUP (SEE FIGURE 2) DS2483 PULLDOWN 1-Wire SLAVE PULLDOWN
V
CC
V
IH1
V
IL1
0V
RESET PULSE PRESENCE/SHORT DETECT
t
RSTL
t
SI
t
MSP
t
RSTH
t
F1
PRESENCE PULSE
APU CONTROLLED
EDGE