Datasheet

DS2480B
Maxim Integrated ........................................................................................................................................................................................... 21
SINGLE BIT WITH STRONG PULLUP
Similar to the Pulse command, the Single Bit command also allows generating a strong pullup
immediately following a time slot. The strong pullup of the Single Bit command, however, is controlled
directly by bit 1 of the command code and therefore needs not be armed. Since the DS2480B remains in
Command Mode when using the Single Bit command, any duration of the strong pullup including infinite
may be selected.
Figure 9a. SINGLE BIT WITH STRONG PULLUP, PREDEFINED DURATION
Figure 9 shows the timing of the Single Bit command immediately following strong pullup. For
predefined duration (Figure 9a) the timing is as follows: At t
1
the time slot is completed. Now the
DS2480B activates the strong pullup and simultaneously starts sending the response byte of the Single Bit
command to the host. At t
2
the strong pullup ends and the DS2480B sends out a pulse response byte. The
idle time between t
2
and t
3
is comprised of the time to transmit the pulse response byte, plus the response
time of the host plus the time to transmit the command and/or data to generate the next time slot.
Figure 9b. SINGLE BIT WITH STRONG PULLUP, INFINITE DURATION
For infinite duration (Figure 9b) the strong pullup also begins immediately after the time slot is
completed. To end the strong pullup, the DS2480B must receive a Termination command, code F1h,
which occurs at t
2
. The termination command does not generate a response byte. The DS2480B will then
immediately end the strong pullup and send out a pulse response byte. Everything else is the same as with
predefined duration.