fs7140 ON Semiconductor, fs7140 Datasheet - Page 9

• Manufacturer Part Number: fs7140
• Description: Programmable Phase- Locked Loop Clock Generator
• Manufacturer: ON Semiconductor

during a register write, the data that has been transferred is
ignored.
Random Register Read Procedure
from any register. To perform a read procedure, the R/W bit
that is transmitted after the seven−bit address is a logic−low,
as in the register write procedure. This indicates to the
addressed slave device that a register address will follow
after the slave device acknowledges its device address. The
register address is then written into the slave’s address
pointer.
generates a repeated START condition. The repeated
START terminates the write procedure, but not until after the
slave’s address pointer is set. The slave address is then
resent, with the R/W bit set this time to a logic−high,
indicating to the slave that data will be read. The slave will
acknowledge the device address, and then transmits the
eight−bit word. The master does not acknowledge the
transfer but does generate a STOP condition.
Sequential Register Write Procedure
each register in order. The register pointer is automatically
incremented after each write. This procedure is more
efficient than the random register write if several registers
must be written.
transmitted after the seven−bit device address is a logic−low.
This indicates to the addressed slave device that a register
address will follow after the slave device acknowledges its
device address. The register address is written into the
slave’s address pointer. Following an acknowledge by the
If either a STOP or a repeated START condition occurs
Random read operations allow the master to directly read
Following an acknowledge by the slave, the master
Sequential write operations allow the master to write to
To initiate a write procedure, the R/W bit that is
http://onsemi.com
9
slave, the master is allowed to write up to eight bytes of data
into the addressed register before the register address pointer
overflows back to the beginning address.
must occur before the next data byte is sent.
acknowledge to the host. The register update does not wait
for the STOP condition to occur. Registers are therefore
updated at different times during a sequential register write.
Sequential Register Read Procedure
each register in order. The register pointer is automatically
incremented by one after each read. This procedure is more
efficient than the random register read if several registers
must be read.
transmitted after the seven−bit address is a logic−low, as in
the register write procedure. This indicates to the addressed
slave device that a register address will follow after the slave
device acknowledges its device address. The register
address is then written into the slave’s address pointer.
generates a repeated START condition. The repeated
START terminates the write procedure, but not until after the
slave’s address pointer is set. The slave address is then
resent, with the R/W bit set this time to a logic−high,
indicating to the slave that data will be read. The slave will
acknowledge the device address, and then transmits all eight
bytes of data starting with the initial addressed register. The
register address pointer will overflow if the initial register
address is larger than zero. After the last byte of data, the
master does not acknowledge the transfer but does generate
a STOP condition.
An acknowledge by the device between each byte of data
Registers are updated every time the device sends an
Sequential read operations allow the master to read from
To perform a read procedure, the R/W bit that is
Following an acknowledge by the slave, the master