
DS1678 Real-Time Event Recorder
4 of 25
Note 1:
Limits at -40
C are guaranteed by design and not production tested.
Note 2:
All voltages referenced to ground.
Note 3:
After this period, the first clock pulse is generated.
Note 4:
A device must initially provide a hold time of at least 300ns for the SDA signal to bridge the undefined region of the falling edge
of SCL. The maximum tHD:DAT need only be met if the device does not stretch the LOW period (tLOW) of the SCL signal.
Note 5:
A fast-mode device can be used in a standard-mode system, but the requirement tSU:DAT > 250ns must then be met. This is
automatically the case if the device does not stretch the LOW period of the SCL signal. If such a device does stretch the LOW
period of the SCL signal, it must output the next data bit to the SDA line tR(MAX) + tSU:DAT = 1000 + 250 = 1250ns before the SCL
line is released.
Note 6:
CB—Total capacitance of one bus line in pF.
Note 7:
tR and tF are measured with a 1.7k pullup resistor, 200pF pullup capacitor, 1.7k pulldown resistor, and 5pF
pulldown capacitor.
I
2C COMMUNICATION TIMING DIAGRAM
SU:STO
t
HD:STA
t
t SU:STA
SU:DAT
t
tHIGH
R
t
tLOW
tHD:STA
SCL
START
SDA
STOP
tBUF
tF
REPEATED
START
tHD:DAT