Rainbow Electronics DS2482-800 - Manual (Page 14)

DS2482-800: Eight-Channel 1-Wire Master
14 of 22
1-Wire Read Byte
Command Code 96h
Command Parameter None
Description
Generates eight read data time slots on the selected 1-Wire IO channel
and stores result in the Read Data Register.
Typical Use
To read data from a 1-Wire IO channel; equivalent to executing eight 1-
Wire Single Bit commands with V = 1 (write 1 time slot), but faster due to
less I²C traffic.
Restriction
1-Wire activity must have ended before the DS2482 can process this
command.
Error Response
Command code will not be acknowledged if 1WB = 1 at the time the
command code is received and the command will be ignored.
Command Duration
8 × t
SLOT
+ maximum 262.5ns, counted from the falling SCL edge of the
command code acknowledge bit.
1-Wire Activity
Begins maximum 262.5ns after the falling SCL edge of the command
code acknowledge bit.
Read Pointer Position
Status Register (for busy polling)
NOTE: To read the data byte received from the 1-Wire IO channel, issue
the Set Read Pointer command and select the Read Data Register. Then
access the DS2482 in read mode.
Status Bits Affected 1WB (set to 1 for 8 × t
SLOT
)
Configuration Bits Affected 1WS, APU apply
1-Wire Triplet
Command Code 78h
Command Parameter Direction Byte
Description
Generates three times slots, two read-time slots and one-write time slot, at
the selected 1-Wire IO channel. The type of write-time slot depends on the
result of the read-time slots and the direction byte.
The direction byte determines the type of write-time slot if both read-time
slots are 0 (a typical case). In this case the DS2482 will generate a write-1
time slot if V = 1 and a write-0 time slot if V = 0.
If the read-time slots are 0 and 1, there will follow a write 0 time slot.
If the read-time slots are 1 and 0, there will follow a write 1 time slot.
If the read-time slots are both 1 (error case), the subsequent write time
slot will be a write 1.
Typical Use
To perform a 1-Wire Search ROM sequence; a full sequence requires this
command to be executed 64 times to identify and address one device.
Restriction
1-Wire activity must have ended before the DS2482 can process this
command.
Error Response
Command code and direction byte will not be acknowledged if 1WB = 1 at
the time the command code is received and the command will be ignored.
Command Duration
3 × t
SLOT
+ maximum 262.5ns, counted from the falling SCL edge of the
first bit (MS bit) of the direction byte.
1-Wire Activity
Begins maximum 262.5ns after the falling SCL edge of the MS bit of the
direction byte.
Read Pointer Position Status Register (for busy polling)
Status Bits Affected
1WB (set to 1 for 3 × t
SLOT
)
SBR is updated at the first t
MSR
TSB and DIR are updated at the second t
MSR
(i.e., at t
SLOT
+ t
MSR
)
Configuration Bits Affected 1WS, APU apply