PCF8531U NXP [NXP Semiconductors], PCF8531U Datasheet - Page 27

• Manufacturer Part Number: PCF8531U
• Description: 34 x 128 pixel matrix driver
• Manufacturer: NXP [NXP Semiconductors]

NXP Semiconductors
PCF8531_4
Product data sheet
11.1.4 Acknowledge
Acknowledge on the I
an acknowledge bit. The acknowledge bit is a HIGH signal put on the bus by the
transmitter, during which time the master generates an extra acknowledge related clock
pulse. A slave receiver addressed must generate an acknowledge after the reception of
each byte.
Also, a master receiver must generate an acknowledge after the reception of each byte
that has been clocked out of the slave transmitter. The device that acknowledges must
pull-down the SDA line during the acknowledge clock pulse so that the SDA line is stable
LOW during the HIGH period of the acknowledge-related clock pulse (set-up and hold
times must be taken into consideration). A master receiver must signal an “end of data” to
the transmitter by not generating an acknowledge on the last byte that has been clocked
out of the slave. In this event, the transmitter must leave the data line HIGH to enable the
master to generate a STOP condition.
Fig 16. System configuration
Fig 17. Acknowledge on the I
•
•
•
Multi-master: more than one master can attempt to control the bus at the same time
without corrupting the message
Arbitration: procedure to ensure that, if more than one master simultaneously tries to
control the bus, only one is allowed to do so and the message is not corrupted
Synchronization: procedure to synchronize the clock signals of two or more devices.
SCL
SDA
by transmitter
data output
by receiver
data output
TRANSMITTER/
SCL from
RECEIVER
master
MASTER
condition
START
2
C-bus is shown in
S
Rev. 04 — 13 June 2008
RECEIVER
SLAVE
2
C-bus
1
TRANSMITTER/
Figure
RECEIVER
SLAVE
2
17. Each byte of eight bits is followed by
TRANSMITTER
MASTER
not acknowledge
34 x 128 pixel matrix driver
acknowledge
8
acknowledgement
clock pulse for
PCF8531
TRANSMITTER/
© NXP B.V. 2008. All rights reserved.
RECEIVER
MASTER
9
mbc602
mga807
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