Rainbow Electronics DS1920 User Manual
Page 17
DS1920
17 of 22
DS1920 MEMORY AND CONTROL FUNCTION COMMANDS Table 2
INSTRUCTION
DESCRIPTION
PROTOCOL
1-WIRE BUS
AFTER ISSUING
PROTOCOL
NOTES
TEMPERATURE CONVERSION COMMANDS
Convert
Temperature
Initiates temperature
conversion
44H
strong pullup
1
MEMORY COMMANDS
Read Scratchpad
Reads bytes from scratchpad
and reads CRC byte.
BEH
bytes> Write Scratchpad Writes bytes into scratchpad 4EH bytes at addr. 2 and addr. 3> Copy Scratchpad Copies Scratchpad into 48H strong pullup 2 Recall Recalls values stored in B8H idle NOTES: 1. Temperature conversion takes up to 0.5 seconds. After receiving the Convert Temperature command, the data line for the DS1920 must be held high for at least 0.5 seconds to provide power during the 2. After receiving the Copy Scratchpad command, the data line for the DS1920 must be held high for at least 10 ms to provide power during the copy process. As such, no other activity may take place on READ/WRITE TIMING DIAGRAM Figure 11 Write-1 Time Slot 60 µ s ≤ t SLOT < 120 µ s 1 µ s ≤ t LOW1 < 15 µ s 1 µ s ≤ t REC < ∞ RESISTOR MASTER
at addresses 2 and 3 (TH and
TL temperature triggers).
nonvolatile memory
(addresses 2 and 3 only).
nonvolatile memory into
scratchpad (temperature
triggers).
conversion process. As such, no other activity may take place on the 1-Wire bus for at least this
period after a Convert Temperature command has been issued.
the 1-Wire bus for at least this period after a Copy Scratchpad command has been issued.