DS1822-PAR_07 DALLAS [Dallas Semiconductor], DS1822-PAR_07 Datasheet - Page 14

• Manufacturer Part Number: DS1822-PAR_07
• Description: Econo 1-Wire Parasite-Power Digital Thermometer
• Manufacturer: DALLAS [Dallas Semiconductor]

The DS1822-PAR samples the 1-Wire bus during a window that lasts from 15μs to 60μs after the master
initiates the write-time slot. If the bus is high during the sampling window, a 1 is written to the DS1822-
PAR. If the line is low, a 0 is written to the DS1822-PAR.
READ/WRITE-TIME SLOT TIMING DIAGRAM Figure 12
READ-TIME SLOTS
The DS1822-PAR can only transmit data to the master when the master issues read-time slots. Therefore,
the master must generate read-time slots immediately after issuing a Read Scratchpad [BEh] command,
so that the DS1822-PAR can provide the requested data. In addition, the master can generate read-time
slots after issuing a Recall E
PAR FUNCTION COMMAND section.
All read-time slots must be a minimum of 60 μs in duration with a minimum of a 1μs recovery time
between slots. A read-time slot is initiated by the master device pulling the 1-Wire bus low for a
minimum of μs and then releasing the bus (see Figure 12). After the master initiates the read-time slots,
the DS1822-PAR will begin transmitting a 1 or 0 on bus. The DS1822-PAR transmits a 1 by leaving the
bus high and transmits a 0 by pulling the bus low. When transmitting a 0, the DS1822-PAR will release
the bus by the end of the time slot, and the bus will be pulled back to its high idle state by the pullup
1-WIRE BUS
1-WIRE BUS
V
GND
V
GND
PU
PU
> 1μs
OF SLOT
START
15μs
15μs
MASTER WRITE “0” SLOT
MASTER READ “0” SLOT
LINE TYPE LEGEND
60μs < T
2
MIN
Master samples
15μs
[B8h] command to find out the recall status as explained in the DS1822-
DS1822-PAR samples
Bus master pulling low
Resistor pullup
X
TYP
“0” < 120μs
45μs
MAX
30μs
14 of 19
> 1 μs
OF SLOT
START
DS1822-PAR pulling low
15μs
15μs
1μs < T
1 μs < T
MASTER WRITE “1” SLOT
> 1μs
MASTER READ “1” SLOT
REC
REC
<
MIN
<
∞
Master samples
15μs
∞
DS1822-PAR samples
TYP
MAX
30μs
DS1822-PAR