MAX6956 Maxim, MAX6956 Datasheet - Page 8

• Manufacturer Part Number: MAX6956
• Description: 2-Wire-Interfaced / 2.5V to 5.5V / 20-Port or 28-Port LED Display Driver and I/O Expander
• Manufacturer: Maxim

has finished communicating with the slave, it issues a
STOP (P) condition by transitioning SDA from low to
high while SCL is high. The bus is then free for another
transmission (Figure 3).
One data bit is transferred during each clock pulse.
The data on SDA must remain stable while SCL is high
(Figure 4).
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port LED Display Driver and I/O Expander
Figure 3. Standard Stop Conditions
8
Figure 2. 2-Wire Serial Interface Timing Details
Figure 4. Bit Transfer
_______________________________________________________________________________________
SDA
SCL
t
HD, STA
START CONDITION
SDA
SCL
t
LOW
CONDITION
SDA
SCL
t
START
R
S
t
HIGH
t
SU, DAT
t
F
DATA LINE STABLE;
Bit Transfer
t
HD, DAT
DATA VALID
t
SU, STA
REPEATED START CONDITION
CHANGE OF DATA ALLOWED
The acknowledge bit is a clocked 9th bit, which the
recipient uses to handshake receipt of each byte of
data (Figure 5). Thus, each byte transferred effectively
requires 9 bits. The master generates the 9th clock
pulse, and the recipient pulls down SDA during the
acknowledge clock pulse, such that the SDA line is sta-
ble low during the high period of the clock pulse. When
the master is transmitting to the MAX6956, the
MAX6956 generates the acknowledge bit because the
t
HD, STA
CONDITION
STOP
P
t
SU, STO
STOP CONDITION
Acknowledge
t
BUF
START CONDITION