BCM43455 Preliminary Data Sheet
I2S Interface
2
I S Timing
Note: Timing values specified in Table 14 are relative to high and low threshold levels.
Table 14: Timing for I2S Transmitters and Receivers
Transmitter
Lower LImit
Receiver
Upper Limit
Lower Limit
Upper Limit
Min.
Max.
Min.
Max.
Min.
Max.
Min.
Max.
Notes
a
Clock Period T
T
–
–
–
T
–
–
–
tr
r
Master Mode: Clock generated by transmitter or receiver
b
b
HIGH t
0.35T
0.35T
–
–
–
–
–
–
0.35T
0.35T
–
–
–
–
–
–
HC
tr
tr
tr
tr
LOWt
LC
Slave Mode: Clock accepted by transmitter or receiver
c
c
d
HIGH t
–
–
–
0.35T
0.35T
–
–
–
–
–
–
–
–
0.35T
0.35T
–
–
–
–
–
–
–
HC
LC
tr
tr
tr
tr
LOW t
–
Rise time t
0.15T
RC
tr
Transmitter
Delay t
e
d
–
0
–
–
–
–
0.8T
–
–
–
–
–
–
–
–
–
dtr
Hold time t
htr
Receiver
f
f
Setup time t
–
–
–
–
–
–
–
–
–
–
0.2T
0
–
–
–
–
sr
r
Hold time t
hr
a. The system clock period T must be greater than Ttr and Tr because both the transmitter and receiver have to be
able to handle the data transfer rate.
b. At all data rates in master mode, the transmitter or receiver generates a clock signal with a fixed mark/space
ratio. For this reason, tHC and tLC are specified with respect to T.
c. 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 0.35Tr, any clock that meets the
requirements can be used.
d. Because the delay (tdtr) and the maximum transmitter speed (defined by Ttr) are related, a fast transmitter driven
by a slow clock edge can result in tdtr not exceeding tRC which means thtr becomes zero or negative. Therefore,
the transmitter has to guarantee that thtr is greater than or equal to zero, so long as the clock rise-time tRC is not
more than tRCmax, where tRCmax is not less than 0.15Ttr.
e. 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.
f. The data setup and hold time must not be less than the specified receiver setup and hold time.
Broadcom®
November 5, 2015 • 43455-DS109-R
Page 58
BROADCOM CONFIDENTIAL
CYPRESS [ CYPRESS ]
