ds1863 Maxim Integrated Products, Inc., ds1863 Datasheet - Page 17

• Manufacturer Part Number: ds1863
• Description: Ds1863 Burst-mode Pon Controller With Integrated Monitoring
• Manufacturer: Maxim Integrated Products, Inc.

specific memory address to begin a data transfer. A
repeated START condition is issued identically to a nor-
mal START condition. See the timing diagram for
applicable timing.
Bit Write: Transitions of SDA must occur during the low
state of SCL. The data on SDA must remain valid and
unchanged during the entire high pulse of SCL plus the
setup and hold-time requirements (Figure 9). Data is shift-
ed into the device during the rising edge of the SCL.
Bit Read: At the end of a write operation, the master
must release the SDA bus line for the proper amount of
setup time before the next rising edge of SCL during a
bit read. The device shifts out each bit of data on SDA at
the falling edge of the previous SCL pulse and the data
bit is valid at the rising edge of the current SCL pulse.
Remember that the master generates all SCL clock
pulses including when it is reading bits from the slave.
Acknowledgement (ACK and NACK): An Acknowledge-
ment (ACK) or Not Acknowledge (NACK) is always the
9th bit transmitted during a byte transfer. The device
receiving data (the master during a read or the slave
during a write operation) performs an ACK by transmit-
ting a zero during the 9th bit. A device performs a
NACK by transmitting a one during the 9th bit. Timing
for the ACK and NACK is identical to all other bit writes.
An ACK is the acknowledgment that the device is prop-
erly receiving data. A NACK is used to terminate a read
sequence or as an indication that the device is not
receiving data.
Byte Write: A byte write consists of 8 bits of information
transferred from the master to the slave (most signifi-
cant bit first) plus a 1-bit acknowledgement from the
slave to the master. The 8 bits transmitted by the mas-
Figure 9. I
SDA
SCL
NOTE: TIMING IS REFERENCED TO V
2
C Timing Diagram.
STOP
t
BUF
START
IL(MAX)
t
HD:STA
t
LOW
AND V
IH(MIN)
.
____________________________________________________________________
t
R
t
HD:DAT
t
F
t
HIGH
Burst-Mode PON Controller
With Integrated Monitoring
t
SU:DAT
ter are done according to the bit write definition and the
acknowledgement is read using the bit read definition.
Byte Read: A byte read is an 8-bit information transfer
from the slave to the master plus a 1-bit ACK or NACK
from the master to the slave. The 8 bits of information
that are transferred (most significant bit first) from the
slave to the master are read by the master using the bit
read definition, and the master transmits an ACK using
the bit write definition to receive additional data bytes.
The master must NACK the last byte read to terminate
communication so the slave will return control of SDA to
the master.
Slave Address Byte: Each slave on the I
responds to a slave addressing byte (Figure 10) sent
immediately following a START condition. The slave
address byte contains the slave address in the most sig-
nificant 7 bits and the
The DS1863’s slave address can be configured to any
value between 00h to FEh using the Device Address
Byte (Table 02h, Register 8Ch). The user also has to set
the ASEL bit (Table 02h, Register 89h) for this address to
be active. The default address is A2h (see Figure 10). By
writing the correct slave address with R/W = 0, the mas-
ter indicates it will write data to the slave. If R/W = 1, the
master will read data from the slave. If an incorrect slave
address is written, the DS1863 will assume the master is
communicating with another I
communications until the next START condition is sent.
Memory Address: During an I
master must transmit a memory address to identify the
memory location where the slave is to store the data.
The memory address is always the second byte trans-
mitted during a write operation following the slave
address byte.
REPEATED
START
t
SU:STA
t
HD:STA
R/W bit in the least significant bit.
2
C device and ignore the
2
t
C write operation, the
SP
t
SU:STO
2
C bus
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