Parallax BASIC Stamp 2e Programming Manual page 204

OWIN - BASIC Stamp Command Reference
Command Value (in Hex)
Read ROM $33
Match ROM $55
Skip ROM $CC
Search ROM $F0
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 OWIN command will read data at this point in the
transaction. A read is accomplished by generating a brief low-pulse and
sampling the line within 15 µ s of the falling edge of the pulse. This is
called a "Read Slot." Figure 5.19 shows typical Read Slots performed by
the BASIC Stamp. See the OWOUT command for information on Write
Slots.
+5 (vdd)
0 (vss)
Page 202 • BASIC Stamp Programming Manual 2.0b • www.parallaxinc.com
Reads the 64-bit ID of the 1-wire device. This command
can only be used if there is a single 1-wire device on the
line.
This command, followed by a 64-bit ID, allows the BASIC
Stamp to address a specific 1-wire device.
Address a 1-wire device without its 64-bit ID. This
command can only be used if there is a single 1-wire
device on the line.
Reads the 64-bit IDs of all the 1-wire devices on the line. A
process of elimination is used to distinguish each unique
device.
Recovery Period
Apx 4 s µ
BASIC Stamp's BASIC Stamp's
Read "0" Slot Read "1" Slot
µ
Apx. 72 s Apx. 72 s
driven by BASIC Stamp
driven by 1-wire device or pulled-up by 5 k resister
time when BASIC Stamp samples line (apx 1 - 10 s)
Action
µ
Apx 8 s
µ
Apx 4 s
µ
Ω
µ
Table 5.47: 1-wire ROM Function
Commands.
Figure 5.19: Example Read Slot.