149
MC95FG308 / MC95FG208
ABOV Semiconductor Co., Ltd.
11.9.5 Data Transfer
Every byte put on the SDA line must be 8-bit long. The number of bytes that can be transmitted per transfer is
unlimited. Each byte has to be followed by an acknowledge bit. Data is transferred with the most significant bit (MSB)
first. If a slave can’t receive or transmit another complete byte of data until it has performed some other function, it can
hold the clock line SCL LOW to force the master into a wait state. Data transfer then continues when the slave is ready
for another byte of data and releases clock line SCL.
Figure 11.54
STOP or Repeated START Condition
11.9.6 Acknowledge
The acknowledge related clock pulse is generated by the master. The transmitter releases the SDA line (HIGH) during
the acknowledge clock pulse. The receiver must pull down the SDA line during the acknowledge clock pulse so that it
remains stable LOW during the HIGH period of this clock pulse. When a slave is addressed by a master (Address
Packet), and if it is unable to receive or transmit because it’s performing some real time function, the data line must be
left HIGH by the slave. And also, when a slave addressed by a master is unable to receive more data bits, the slave
receiver must release the SDA line (Data Packet). The master can then generate either a STOP condition to abort the
transfer, or a repeated START condition to start a new transfer.
If a master receiver is involved in a transfer, it must signal the end of data to the slave transmitter by not generating an
acknowledge on the last byte that was clocked out of the slave. The slave transmitter must release the data line to
allow the master to generate a STOP or repeated START condition.
Figure 11.55
Acknowledge on the I2C-Bus
1
2
8
Data Output
By Transmitter
9
ACK
NACK
Clock pulse for ACK
Data Output
By Receiver
SCL From MASTER
START or Repeated
START Condition
S
or
Sr
STOP or Repeated
START Condition
Sr
or
P
MSB
Acknowledgement
Signal form Slave
Acknowledgement
Signal form Slave
Byte Complete,
Interrupt within Device
Clock line held low while
interrupts are served.
1
9
1
9
ACK
ACK
SDA
SCL
Sr
P
Содержание MC95FG208 Series
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Страница 16: ...16 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 3 32 Pin LQFP Package...
Страница 17: ...17 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 4 28 Pin SOP Package...
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Страница 20: ...20 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 7 28 Pin TSSOP Package...
Страница 21: ...21 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 8 20 Pin SOP Package...
Страница 22: ...22 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 9 20 Pin TSSOP Package...
Страница 23: ...23 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 10 16 Pin SOP Package...
Страница 24: ...24 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 11 16 Pin TSSOP Package...