CS1630/31
Slave Address
(1 Byte and Acknowledge)
Data Transferred
(2 Bytes and Acknowledge)
Device Address
Register Address
(7-bit)
S
0
A
0
A
Data
A
P
(7-bit)
Stop
Condition
Start
Condition
‘0’ = Write ‘0’ = Single
‘A’ = Acknowledge
(SDA Low)
Data Transferred
(n Bytes and Acknowledge)
Slave Address
(1 Byte and Acknowledge)
Device Address
Register Address
(7-Bit)
… ...
S
0
A
1
A
Data
A
Data
A
P
(7-Bit)
Start
‘0’ = Write ‘1’ = Block
‘A’ = Acknowledge (SDA Low)
Stop
Condition
Condition
From Slave to Master
From Master to Slave
Figure 29. Frame Formats for Write Operation
To perform a single shadow register write, a write to the
Control Port must be used to set up the shadow register
address and the BLK/SGL configuration bit (indicating a single
write operation). To initiate a single write operation, a Start
condition followed by a slave address of 0x20 (7 MSB device
address = ‘0010000’ and the LSB R/W = ‘0’ for a write
operation) is sent at the start of the message. The most
significant bit of the second byte is cleared to ‘0’ to indicate a
single byte write. The remaining 7 bits of the second byte
represent the shadow register address of the write operation.
After receiving the Acknowledge from the Control Port, the
master should terminate the message by sending a Stop
condition. The protocol for a single write operation is shown as
the top frame in Figure 29.
0x01 to 0x04). The value of the Lockout Key is user
programmable and stored in OTP memory (see "Lockout Key
(LOCK0, LOCK1, LOCK2, LOCK3) – Address 1 - 4" on
page 29).
To unlock the Control Port, the proper programmed Lockout
Key is written to the 32-bit Lockout Key shadow registers
LOCK3, LOCK2, LOCK1, and LOCK0. The Lockout Key must
be written in ascending address order for the lockout to be
disabled. The MODE bit in register Config0 is set to ‘1’, the
Color Polynomial Coefficient registers P10_MSB, P10_LSB,
P01_MSB, and P01_LSB (at register address 0x09, 0x0A,
0x0F, and 0x10) are appended to the Lockout Key to increase
security. If the wrong Lockout Key is written to the shadow
resisters when attempting to disable the lockout feature, the
part cannot be unlocked until a reset cycle occurs.
To initiate a block write operation, a Start condition followed by
a slave address of 0x20 (7 MSB device address =
‘0010000’and the LSB R/W = ‘0’ for a write operation) is sent
at the start of the message. The MSB of the second byte is set
to ‘1’ to indicate a block write. The remaining 7 bits of the
second byte represent the starting shadow register address of
the write operation. The slave continues to send data bytes
until the master sends a Stop condition after receiving the
Acknowledge, signifying the end of the block write message.
The protocol for a block write operation is illustrated by the
bottom frame in Figure 29. Block writes will wrap around from
shadow register address 127 to 0 if a Stop condition is not
received.
In lockout mode, the Control Port disables the following
operations through the I2C communication port:
• I2C read operations from OTP shadow registers (value
of 0x0 will be read through control port)
• I2C write operations to lockout enabled or key shadow
registers (including read operations through PLC)
• Direct OTP memory read or write (including reads/writes
through PLC)
Write operations to either OTP or test space (except OTP
Lockout Key) are allowed in lockout mode.
5.12 OTP Memory
5.11.5 Customer I2C Lockout
At startup, the contents of the OTP memory are read into
shadow registers that make up a register file. Access to the
OTP memory values is accomplished by reading and writing
to the OTP corresponding address locations in that register
file. To program the part, each unprogrammed address
location must be filled with an appropriate value. Next, a CRC
is calculated corresponding to the OTP space that is being
programmed. Lastly, two special registers are written to
initiate a burn/program cycle.
The CS1630/31 provides a mechanism that locks or disables
the I2C control port. This feature provides security against
potential access to proprietary register settings and OTP
memory (color compensation) through the I2C control port. To
enable the lockout feature, the LOCKOUT bit is set to ‘1’ in the
Config0 register (see "Configuration 0 (Config0) – Address 0"
on page 29) and setting a 32-bit Lockout Key in registers
LOCK3, LOCK2, LOCK1, and LOCK0 (at register address
DS954F2
25
APEX [ CIRRUS LOGIC ]
