AT88SC0404CA-TH Atmel, AT88SC0404CA-TH Datasheet - Page 29

• Manufacturer Part Number: AT88SC0404CA-TH
• Description: IC EEPROM 4KBIT 4MHZ 8TSSOP
• Manufacturer: Atmel
• Series: CryptoMemory®r

Specifications of AT88SC0404CA-TH

• Format - Memory: EEPROMs - Serial
• Memory Type: EEPROM
• Memory Size: 4K (512 x 8)
• Speed: 4MHz
• Interface: I²C, 2-Wire Serial
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8.3.
8.3.1. WRITE Command Format
8.3.2. Read Command Format
28
Command Format
Most Atmel
characterized by a zero in the LSB of the first byte (device address). The only exception is the Random Read command
that has a one in the LSB of the device address byte.
The host generates all command and data bytes within a write transaction and sends these to the device. The device
acknowledges each byte.
Figure 12. Atmel CryptoMemory WRITE Command
The number of bytes CryptoMemory can write within each call of a write command is constrained by the physical page
size of the EEPROM memory. The maximum number of bytes to write for each call to the WRITE command is $10. All
CryptoMemory Write commands comply with the format for the TWI write command.
The CryptoMemory READ commands (Read User Zone, System READ and Random Read) do not comply with the
format of the TWI READ command. The CryptoMemory Read User Zone and System READ commands closely
resemble the TWI WRITE command format by having a zero in the LSB in the device address byte. The Random Read
command closely resembles the format for the TWI READ command but requires additional steps to specify the read
address.
Normal Read: $B2 or $B6 (Read User Zone or System READ)
The CryptoMemory Normal Read command looks like a TWI write command (LSB of the fist byte = 0) but after the
fourth byte of the command the CryptoMemory device will begin to send data back on the bus. The number of bytes
sent by CryptoMemory will be equal to the value of N.
Figure 13. Atmel CryptoMemory Normal Read Command
The response of CryptoMemory will cause contention with the host on a standard TWI bus. Typically CryptoMemory
cannot be used on a standard TWI bus but requires a modified TWI protocol to account for the unique read command
format.
Atmel AT88SC0104/0204/0404/0808/CA
R
S
T
A
T
R
S
T
A
T
Command
Command
xxxx xxx0
xxxx xxx0
WRITE
READ
®
CryptoMemory
C
A
C
K
A
K
Address 1
Address 1
0000 0000
0000 0000
®
commands have the same format as a two wire interface (TWI) write command
A
C
K
A
C
K
Address 2
Address 2
0a6-- ---a0
0a6-- ---a0
A
C
K
C
A
K
n7--- ---n0
n7--- ---n0
N
N
A
C
K
C
A
K
d7--- ---d0
d7--- ---d0
Data
Data
A
C
K
A
C
K
Data x N
d7--- ---d0
Data x N
d7--- ---d0
N
C
A
K
A
C
K
O
S
T
P
O
S
T
P
8664C–CRYPT–01/10