ds2482-101 Maxim Integrated Products, Inc., ds2482-101 Datasheet - Page 7

• Manufacturer Part Number: ds2482-101
• Description: Single-channel 1-wire Master With Sleep Mode
• Manufacturer: Maxim Integrated Products, Inc.

Figure 2. Rising Edge Pullup
Figure 3. Presence-Pulse Masking
The PPM bit controls whether the DS2482-101 masks
the leading edge (falling) of presence pulses. When
PPM = 0, masking is disabled. Presence-pulse masking
applies only to standard 1-Wire speed (1WS = 0); this
bit has no function if 1WS = 1 (overdrive speed).
Presence-pulse masking can improve the performance
of large 1-Wire networks because it prevents the fast
falling edge of a presence pulse generated by a 1-Wire
slave device from propagating through the network and
Single-Channel 1-Wire Master with Sleep Mode
V
CC
0V
V
V
IL1(MAX)
IH1(MIN)
_______________________________________________________________________________________
V
CC
0V
Presence-Pulse Masking (PPM)
1-Wire BUS IS DISCHARGED
PULLUP
DS2482-101 PULLDOWN
RESET PULSE
t
RSTL
APU = 1
t
1
APU CONTROLLED EDGE
t
2
t
APUOT
t
PPM1
being reflected. Reflections can cause glitches in the
network that, in turn, can cause slave devices to lose
synchronization with the 1-Wire master.
Figure 3 shows the timing references for the presence-
pulse masking. If enabled (PPM = 1), the DS2482-101
begins pulling the 1-Wire line low at t
reset low time t
t
1-Wire line low. The falling edge of the presence-pulse
mask is slew-rate controlled.
1-Wire SLAVE PULLDOWN
DS2482-101 PULLDOWN WITH PPM = 1; STANDARD SPEED ONLY
PPM2
t
PPM2
, at which a 1-Wire slave, if present, is pulling the
t
3
PRESENCE PULSE
t
RSTH
APU = 0
RSTL
is expired. The pulldown ends at
RESISTIVE
PULLUP
PPM1
after the
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