M34F04 Datasheet, PDF (11/20 Pages) STMicroelectronics – 4Kbit Serial I2C Bus EEPROM With Hardware Write Control on Top Half of Memory

Figure 9. Read Mode Sequences
CURRENT
ADDRESS
READ
ACK
NO ACK
DEV SEL
DATA OUT
R/W
M34F04
RANDOM
ADDRESS
READ
ACK
ACK
ACK
NO ACK
DEV SEL *
BYTE ADDR
DEV SEL *
DATA OUT
R/W
R/W
SEQUENTIAL
CURRENT
READ
SEQUENTIAL
RANDOM
READ
ACK
ACK
DEV SEL
DATA OUT 1
R/W
ACK
NO ACK
DATA OUT N
ACK
ACK
ACK
ACK
DEV SEL *
BYTE ADDR
DEV SEL *
DATA OUT 1
R/W
R/W
ACK
NO ACK
DATA OUT N
AI01942
Note: 1. The seven most significant bits of the Device Select Code of a Random Read (in the 1^st and 3^rd bytes) must be identical.
Read Operations
Current Address Read
Read operations are performed independently of
the state of the Write Control (WC) signal.
Random Address Read
A dummy Write is performed to load the address
into the address counter (as shown in Figure 9) but
without sending a Stop condition. Then, the bus
master sends another Start condition, and repeats
the Device Select Code, with the RW bit set to 1.
The device acknowledges this, and outputs the
contents of the addressed byte. The bus master
must not acknowledge the byte, and terminates
the transfer with a Stop condition.
The device has an internal address counter which
is incremented each time a byte is read. For the
Current Address Read operation, following a Start
condition, the bus master only sends a Device Se-
lect Code with the RW bit set to 1. The device ac-
knowledges this, and outputs the byte addressed
by the internal address counter. The counter is
then incremented. The bus master terminates the
transfer with a Stop condition, as shown in Figure
9, without acknowledging the byte.
Sequential Read
This operation can be used after a Current Ad-
dress Read or a Random Address Read. The bus
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