Specifications

Document Number: 002-29172 Rev. ** Page 34 of 45
PRELIMINARY
CYBT-223058-02
CYBT-253059-02
Figure 16. I
2
C Interface Timing Diagram
I
2
S Interface Timing
I
2
S timing is shown below in Table 29, Figure 17, and Figure 18.
Table 29. Timing for I
2
S Transmitters and Receivers
Transmitter Receiver
NotesLower LImit Upper Limit Lower Limit Upper Limit
Min Max Min Max Min Max Min Max
Clock Period T
T
tr
–––
T
r
–––[17]
Master Mode: Clock generated by transmitter or receiver
HIGH t
HC
0.35T
tr
–––
0.35T
tr
– – – [18]
LOWt
LC
0.35T
tr
–––
0.35T
tr
– – – [18]
Slave Mode: Clock accepted by transmitter or receiver
HIGH t
HC
–
0.35T
tr
–––
0.35T
tr
––[17]
LOW t
LC
–
0.35T
tr
–––
0.35T
tr
––[17]
Rise time t
RC
––
0.15T
tr
– – – – [18]
Transmitter
Delay t
dtr
– – – 0.8T – – – – [19]
Hold time t
htr
0–––––––[18]
Receiver
Setup time t
sr
––––
0.2T
tr
– – – [20]
Hold time t
hr
––––
0.2T
tr
– – – [20]
Notes
17. The system clock period T must be greater than T
tr
and T
r
because both the transmitter and receiver have to be able to handle the data transfer rate.
18. At all data rates in master mode, the transmitter or receiver generates a clock signal with a fixed mark/space ratio. For this reason, t
HC
and t
LC
are specified with
respect to T.
19. In slave mode, the transmitter and receiver need a clock signal with minimum HIGH and LOW periods so that they can detect the signal. So long as the minimum
periods are greater than 0.35T
r
, any clock that meets the requirements can be used.
20. Because the delay (t
dtr
) and the maximum transmitter speed (defined by T
tr
) are related, a fast transmitter driven by a slow clock edge can result in tdtr not exceeding
t
RC
which means t
htr
becomes zero or negative. Therefore, the transmitter has to guarantee that t
htr
is greater than or equal to zero, so long as the clock rise-time
tRC is not more than t
RCmax
, where t
RCmax
is not less than 0.15T
tr
.
21. To allow data to be clocked out on a falling edge, the delay is specified with respect to the rising edge of the clock signal and T, always giving the receiver sufficient
setup time.
22. The data setup and hold time must not be less than the specified receiver setup and hold time.