Datasheet
MAX9880A
Low-Power, High-Performance
Dual I
2
S Stereo Audio Codec
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SCL
SDA
t
R
t
F
t
BUF
START
CONDITION
STOP
CONDITION
REPEATED START CONDITION
START CONDITION
t
SU,STO
t
HD,STA
t
SU,STA
t
HD,DAT
t
SU,DAT
t
LOW
t
HIGH
t
HD,STA
t
SP
Figure 14. 2-Wire Interface Timing Diagram
SCL
SDA
SSrP
Figure 15. START, STOP, and Repeated START Conditions
sequence is framed by a START or repeated START
condition, a not acknowledge, and a STOP condition.
SDA operates as both an input and an open-drain out-
put. A pullup resistor, typically greater than 500Ω, is
required on SDA. SCL operates only as an input. A
pullup resistor, typically greater than 500Ω, is required
on SCL if there are multiple masters on the bus, or if the
single master has an open-drain SCL output. Series
resistors in line with SDA and SCL are optional. Series
resistors protect the digital inputs of the MAX9880A
from high voltage spikes on the bus lines and minimize
crosstalk and undershoot of the bus signals.
Bit Transfer
One data bit is transferred during each SCL cycle. The
data on SDA must remain stable during the high period
of the SCL pulse. Changes in SDA while SCL is high
are control signals (see the
START and STOP
Conditions
section).
START and STOP Conditions
SDA and SCL idle high when the bus is not in use. A
master initiates communication by issuing a START
condition. A START condition is a high-to-low transition
on SDA with SCL high. A STOP condition is a low-to-
high transition on SDA while SCL is high (Figure 15). A
START condition from the master signals the beginning
of a transmission to the MAX9880A. The master termi-
nates transmission and frees the bus by issuing a STOP
condition. The bus remains active if a repeated START
condition is generated instead of a STOP condition.
Early STOP Conditions
The MAX9880A recognizes a STOP condition at any
point during data transmission except if the STOP con-
dition occurs in the same high pulse as a START condi-
tion. For proper operation, do not send a STOP
condition during the same SCL high pulse as the
START condition.