M34D64-R STMICROELECTRONICS [STMicroelectronics], M34D64-R Datasheet - Page 7

• Manufacturer Part Number: M34D64-R
• Description: 64 Kbit Serial I2C Bus EEPROM With Hardware Write Control on Top Quarter of Memory
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

data starts to become overwritten in an implemen-
tation dependent way.
The bus master sends from 1 to 32 bytes of data.
If Write Control (WC) is High, the contents of the
addressed top quarter of the memory location are
Figure 8. Write Cycle Polling Flowchart using ACK
Minimizing System Delays by Polling On ACK
During the internal Write cycle, the device
disconnects itself from the bus, and writes a copy
of the data from its internal latches to the memory
cells. The maximum Write time (t
Tables 13 and 14, but the typical time is shorter.
To make use of this, a polling sequence can be
used by the bus master.
The sequence, as shown in Figure 8, is:
– Initial condition: a Write cycle is in progress.
First byte of instruction
with RW = 0 already
decoded by the device
ReSTART
STOP
NO
NO
w
START Condition
DEVICE SELECT
) is shown in
WRITE Cycle
Addressing the
in Progress
with RW = 0
Operation is
Returned
Memory
ACK
Next
YES
WRITE Operation
WRITE Operation
DATA for the
Continue the
YES
NO
not modified. After each byte is transferred, the in-
ternal byte address counter (the 5 least significant
address bits only) is incremented. The transfer is
terminated by the bus master generating a Stop
condition.
– Step 1: the bus master issues a Start condition
– Step 2: if the device is busy with the internal
followed by a Device Select Code (the first byte
of the new instruction).
Write cycle, no Ack will be returned and the bus
master goes back to Step 1. If the device has
terminated the internal Write cycle, it responds
with an Ack, indicating that the device is ready
to receive the second part of the instruction (the
first byte of this instruction having been sent
during Step 1).
and Receive ACK
Send Address
Condition
START
Random READ Operation
DEVICE SELECT
Continue the
with RW = 1
YES
M34D64
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