DS2413 Maxim, DS2413 Datasheet - Page 13

• Manufacturer Part Number: DS2413
• Description: The DS2413 is a dual-channel programmable I/O 1-Wire® chip
• Manufacturer: Maxim

1-Wire SIGNALING
The DS2413 requires strict protocols to ensure data integrity. The protocol consists of four types of signaling on
one line: Reset Sequence with Reset Pulse and Presence Pulse, Write-Zero, Write-One, and Read-Data. Except
for the Presence pulse, the bus master initiates all falling edges. The DS2413 can communicate at two different
speeds, standard speed, and Overdrive Speed. If not explicitly set into the Overdrive mode, the DS2413
communicates at standard speed. While in Overdrive Mode the fast timing applies to all waveforms.
To get from idle to active, the voltage on the 1-Wire line needs to fall from V
from active to idle, the voltage needs to rise from V
make this rise is seen in Figure 11 as '' and its duration depends on the pullup resistor (R
capacitance of the 1-Wire network attached. The voltage V
logical level, not triggering any events.
Figure 11 shows the initialization sequence required to begin any communication with the DS2413. A Reset Pulse
followed by a Presence Pulse indicates the DS2413 is ready to receive data, given the correct ROM and PIO
Function command. If the bus master uses slew-rate control on the falling edge, it must pull down the line for t
+ t
to standard speed. If the DS2413 is in Overdrive Mode and t
Overdrive Mode. If the device is in Overdrive Mode and t
the communication speed is undetermined.
Figure 11. Initialization Procedure: Reset and Presence Pulse
After the bus master has released the line it goes into receive mode. Now the 1-Wire bus is pulled to V
the pullup resistor, or in case of a DS2482-x00 or DS2480B driver, by active circuitry. When the threshold V
crossed, the DS2413 waits for t
presence pulse, the master must test the logical state of the 1-Wire line at t
The t
DS2413 is ready for data communication. In a mixed population network, t
480µs at standard speed and 48µs at Overdrive speed to accommodate other 1-Wire devices.
F
to compensate for the edge. A t
RSTH
window must be at least the sum of t
V
IHMASTER
V
V
ILMAX
V
V
PUP
0V
TH
TL
t
F
RESISTOR
MASTER TX “RESET PULSE” MASTER RX “PRESENCE PULSE”
PDH
and then transmits a Presence Pulse by pulling the line low for t
RSTL
duration of 480µs or longer exits the Overdrive Mode, returning the device
t
RSTL
PDHMAX
ILMAX
13 of 18
, t
past the threshold V
MASTER
PDLMAX
RSTL

ILMAX
is between 80µs and 480µs, the device will reset, but
, and t
RSTL
t
PDH
is relevant for the DS2413 when determining a
is no longer than 80µs, the device remains in
RECMIN
t
MSP
t
PDL
MSP
. Immediately after t
t
RSTH
TH
RSTH
.
PUP
. The time it takes for the voltage to
should be extended to minimum
below the threshold V
DS2413
t
REC
RSTH
PUP
) used and the
PDL
is expired, the
. To detect a
PUP
TL
. To get
through
TH
RSTL
is