Parallax BASIC Stamp 2e Programming Manual page 212

OWOUT - BASIC Stamp Command Reference
The third part, the Memory Function Command, allows the BASIC Stamp
to address specific memory locations, or features, of the 1-wire device.
Refer to the 1-wire device's data sheet for a list of the available Memory
Function Commands.
Finally, the Transaction/Data section is used to read or write data to the
1-wire device. The OWOUT command will write data at this point in the
transaction. A write is accomplished by generating a low-pulse of a
varying width to indicate a 0 or a 1. This is called a "Write Slot" and must
be at least 60 µ s wide. Figure 5.23 shows typical Write Slots performed by
the BASIC Stamp. See the OWIN command for information on Read Slots.
+5 (vdd)
0 (vss)
The Demo Program uses a Dallas Semiconductor DS1820 Digital
Thermometer device connected as follows. Note that the 4.7 k Ω pull-up
resister is required for proper operation.
Page 210 • BASIC Stamp Programming Manual 2.0b • www.parallaxinc.com
Recovery Period
BASIC Stamp's BASIC Stamp's
Write "0" Slot Write "1" Slot
µ
Apx. 72 s Apx. 72 s
driven by BASIC Stamp
time when 1-wire device samples line (apx 15 - 45 s)
DS1820
(PR35)
1 2 3
Vss
4.7 k
DQ
P0
µ
Apx 8 s
µ
Apx 8 s
µ
µ
Vdd
Ω
Figure 5.23: Example Write Slots.
Figure 5.24: DS1820 Circuit.
NOTE: The 4.7 kΩ resister is
required for proper operation.