IDT5V49EE904
EEPROM PROGRAMMABLE CLOCK GENERATOR CLOCK SYNTHESIZER
IDT®
EEPROM PROGRAMMABLE CLOCK GENERATOR 14
IDT5V49EE904 REV Q 071015
Progread
Note: If the expected read command is not from the next higher register to the previous read or write command, then set a
known “read” register address prior to a read operation by issuing the following command:
Prior to Progread Command Set Register Address
The user can ignore the STOP condition above and use a repeated START condition instead, straight after the slave
acknowledgement bit (i.e., followed by the Progread command):
Progread Command Frame
Progsave
Note:
PROGWRITE is for writing to the IDT5V49EE904 registers.
PROGREAD is for reading the IDT5V49EE904 registers.
PROGSAVE is for saving all the contents of the IDT5V49EE904 registers to the EEPROM.
PROGRESTORE is for loading the entire EEPROM contents to the IDT5V49EE904 registers.
Progrestore
EEPROM Interface
The IDT5V49EE904 can also store its configuration in an internal EEPROM. The contents of the device's internal
programming registers can be saved to the EEPROM by issuing a save instruction (ProgSave) and can be loaded back to
the internal programming registers by issuing a restore instruction (ProgRestore).
To initiate a save or restore using I
2
C, only two bytes are transferred. The Device Address is issued with the read/write bit
set to “0”, followed by the appropriate command code. The save or restore instruction executes after the STOP condition is
issued by the Master, during which time the IDT5V49EE904 will not generate Acknowledge bits. The IDT5V49EE904 will
acknowledge the instructions after it has completed execution of them. During that time, the I
2
C bus should be interpreted
as busy by all other users of the bus.
On power-up of the IDT5V49EE904, an automatic restore is performed to load the EEPROM contents into the internal
programming registers. The IDT5V49EE904 will be ready to accept a programming instruction once it acknowledges its 7-bit
I
2
C address.
SAddress R/W
ACK Command Code ACK Register ACK P
7-bits 0 1-bit 8-bits: xxxx xx00 1-bit 8-bits 1-bit
SAddressR/W ACK ID Byte ACK Data_1 ACK Data_2 ACK Data_last NACK P
7-bits 1 1-bit 8-bits 1-bit 8-bits 1-bit 8-bits 1-bit 8-bits 1-bit
SAddress R/W
ACK Command Code ACK P
7-bits 0 1-bit 8-bits: xxxx xx01 1-bit
SAddress R/W
ACK Command Code ACK P
7-bits 0 1-bit 8-bits: xxxx xx10 1-bit
