M41T00 Datasheet, PDF (6/15 Pages) STMicroelectronics – Serial Access TIMEKEEPER

M41T00
Table 9. Power Down/Up AC Characteristics ⁽¹⁾
(T_A = –40 to 85°C)
Symbol
Parameter
t_PD
SCL and SDA at V_IH before Power Down
t_REC
SCL and SDA at V_IH after Power Up
Note: 1. V_CC fall time should not exceed 5mV/µs.
Figure 5. Power Down/Up Mode AC Waveforms
VCC
VSO
tPD
SDA
SCL
DON'T CARE
Min
Max
Unit
0
ns
10
µs
tREC
AI00596
Acknowledge. Each byte of eight bits is followed
by one acknowledge bit. This acknowledge bit is a
low level put on the bus by the receiver, whereas
the master generates an extra acknowledge relat-
ed clock pulse.
A slave receiver which is addressed is obliged to
generate an acknowledge after the reception of
each byte. Also, a master receiver must generate
an acknowledge after the reception of each byte
that has been clocked out of the slave transmitter.
The device that acknowledges has to pull down
the SDA line during the acknowledge clock pulse
in such a way that the SDA line is a stable Low dur-
ing the High period of the acknowledge related
clock pulse. Of course, setup and hold times must
be taken into account. A master receiver must sig-
nal an end-of-data to the slave transmitter by not
generating an acknowledge on the last byte that
has been clocked out of the slave. In this case, the
transmitter must leave the data line High to enable
the master to generate the STOP condition.
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