M34D64-W_08 STMICROELECTRONICS [STMicroelectronics], M34D64-W_08 Datasheet - Page 16

• Manufacturer Part Number: M34D64-W_08
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Device operation
3.9
16/27
Figure 8.
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
shown in
polling sequence can be used by the bus master.
The sequence, as shown in
●
●
●
First byte of instruction
with RW = 0 already
decoded by the device
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).
Table 11.: AC
Write cycle polling flowchart using ACK
ReStart
Stop
NO
characteristics, but the typical time is shorter. To make use of this, a
Figure 8.: Write cycle polling flowchart using
NO
Start condition
Device select
addressing the
with RW = 0
in progress
operation is
Write cycle
returned
memory
ACK
Next
YES
Write operation
Write operation
Continue the
Data for the
YES
NO
and receive ACK
Send address
condition
Start
Random Read operation
Device select
Continue the
with RW = 1
YES
ACK, is:
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