M24M01 Datasheet, PDF (8/19 Pages) STMicroelectronics – 1 Mbit Serial I²C Bus EEPROM

M24M01
Figure 8. Write Cycle Polling Flowchart using ACK
WRITE Cycle
in Progress
START Condition
DEVICE SELECT
with RW = 0
First byte of instruction
with RW = 0 already
decoded by the device
NO ACK
Returned
YES
Next
NO
Operation is
Addressing the
Memory
ReSTART
YES
Send Address
and Receive ACK
STOP
NO
START
YES
Condition
DATA for the
WRITE Operation
DEVICE SELECT
with RW = 1
Continue the
WRITE Operation
Continue the
Random READ Operation
AI01847C
Minimizing System Delays by Polling On ACK
During the internal Write cycle, the device discon-
nects itself from the bus, and writes a copy of the
data from its internal latches to the memory cells.
The maximum Write time (t_w) is shown in Table
12, 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.
– Step 1: the bus master issues a Start condition
followed by a Device Select Code (the first byte
of the new instruction).
– Step 2: if the device is busy with the internal
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).
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