Rainbow Electronics DS2433 - Manual (Page 20)

DS2433
20 of 21
AC ELECTRICAL CHARACTERISTICS
OVERDRIVE SPEED
(V
PUP
= 2.8V to 6.0V;-40
°
C to +85
°
C)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Time Slot t
SLOT
6 16 ms
Write 1 Low Time t
LOW1
1 2 ms 13
Write 0 Low Time t
LOW0
6 16 ms
Read Low Time t
LOWR
1 2 ms 13
Read Data Valid t
RDV
2 ms 12
Release Time t
RELEASE
0 1.5 4 ms
Read Data Setup t
SU
1 ms 5
Recovery Time t
REC
1 ms
Reset Time High t
RSTH
48 ms 4
Reset Time Low t
RSTL
48 80 ms
Presence Detect High t
PDHIGH
2 6 ms
Presence Detect Low t
PDLOW
8 24 ms
NOTES:
1) All voltages are referenced to ground.
2) V
PUP
= external pullup voltage.
3) Input load is to ground.
4) An additional reset or communication sequence cannot begin until the reset high time has expired.
5) Read data setup time refers to the time the host must pull the 1-Wire bus low to read a bit. Data is
guaranteed to be valid within 1 ms of this falling edge.
6) Capacitance on the data pin could be 800pF when power is first applied. If a 5k W resistor is used to
pull up the data line to V
PUP
, 5 ms after power has been applied the parasite capacitance will not affect
normal communications.
7) The reset low time (t
RSTL
) should be restricted to a maximum of 960 ms, to allow interrupt signaling,
otherwise, it could mask or conceal interrupt pulses.
8) V
IH
is a function of the external pullup resistor and V
PUP
.
9) Under certain low voltage conditions V
ILMAX
may have to be reduced to as much as 0.5V to always
guarantee a Presence Pulse.
10) The Copy Scratchpad takes 5ms maximum during which the voltage on the 1-Wire bus must not fall
below 2.8V.
11) During the execution of the Copy Scratchpad command the DS2433 automatically erases the memory
locations to be written to. No extra steps need to be taken by the bus master.
12) The optimal sampling point for the master is as close as possible to the end time of the t
RDV
period
without exceeding t
RDV
. For the case of a read-one time slot, this maximizes the amount of time for