x76f200 Intersil Corporation, x76f200 Datasheet - Page 3

• Manufacturer Part Number: x76f200
• Description: Secure Serialflash
• Manufacturer: Intersil Corporation

X76F200
Figure 1. X76F200 Device Operation
Retry Counter
The X76F200 contains a retry counter. The retry counter
allows 8 accesses with an invalid password before any
action is taken. The counter will increment with any
combination of incorrect passwords. If the retry counter
overflows, the memory area and both of the passwords
are cleared to "0". If a correct password is received prior
to retry counter overflow, the retry counter is reset and
access is granted.
Device Protocol
The X76F200 supports a bidirectional bus oriented
protocol. The protocol defines any device that sends data
onto the bus as a transmitter and the receiving device as
a receiver. The device controlling the transfer is a master
and the device being controlled is the slave. The master
will always initiate data transfers and provide the clock for
both transmit and receive operations. Therefore, the
X76F200 will be considered a slave in all applications.
Clock and Data Conventions
Data states on the SDA line can change only during SCL
LOW. SDA changes during SCL HIGH are reserved for
indicating start and stop conditions. Refer to Figure 2 and
Figure 3.
LOAD COMMAND/ADDRESS BYTE
USE OF ACK POLLING
VERIFY PASSWORD
ACCEPTANCE BY
LOAD 8-BYTE
READ/WRITE
PASSWORD
BYTES
DATA
3
Start Condition
All commands are preceeded by the start condition,
which is a HIGH to LOW transition of SDA when SCL is
HIGH. The X76F200 continuously monitors the SDA and
SCL lines for the start condition and will not respond to
any command until this condition is met.
A start may be issued to terminate the input of a control
byte or the input data to be written. This will reset the
device and leave it ready to begin a new read or write
command. Because of the push/pull output, a start
cannot be generated while the part is outputting data.
Starts are inhibited while a write is in progress.
Stop Condition
All communications must be terminated by a stop
condition. The stop condition is a LOW to HIGH transition
of SDA when SCL is HIGH. The stop condition is also
used to reset the device during a command or data input
sequence and will leave the device in the standby power
mode. As with starts, stops are inhibited when outputting
data and while a write is in progress.
Acknowledge
Acknowledge is a software convention used to indicate
successful data transfer. The transmitting device, either
master or slave, will release the bus after transmitting
eight bits. During the ninth clock cycle the receiver will
pull the SDA line LOW to acknowledge that it received
the eight bits of data.
The X76F200 will respond with an acknowledge after
recognition of a start condition and its slave address. If
both the device and a write condition have been
selected, the X76F200 will respond with an acknowledge
after the receipt of each subsequent eight-bit word.