BASIC stamp manual v2.2
OWIN – BASIC Stamp Command Reference
Page 300 • BASIC Stamp Syntax and Reference Manual 2.2 • www.parallax.com
Command Value (in Hex) Action
Read ROM $33
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.
Match ROM $55
This command, followed by a 64-bit ID, allows the BASIC
Stamp to address a specific 1-Wire device.
Skip ROM $CC
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.
Search ROM $F0
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.
Table 5.67: 1-Wire ROM Function
Commands.
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.
BASIC Stamp’s
Read “0” Slot
Apx. 72 s
µ
Recovery Period
Apx 8 s
µ
+5 (vdd)
0 (vss)
BASIC Stamp’s
Read “1” Slot
Apx. 72 s
µ
driven by BASIC Stamp
time when BASIC Stamp samples line (apx 1 - 10 s)
µ
Apx 4 s
µ
Apx 4 s
µ
driven by 1-wire device or pulled-up by 5 k resister
Ω
Figure 5.21: Example Read Slot.
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 µs of the falling edge of the pulse. This is
called a "Read Slot." Figure 5.21 shows typical Read Slots performed by
the BASIC Stamp. See the OWOUT command for information on Write
Slots.