24lcs21a Microchip Technology Inc., 24lcs21a Datasheet - Page 11

• Manufacturer Part Number: 24lcs21a
• Description: 1k 2.5v Dual Mode I 2 C? Serial Eeprom
• Manufacturer: Microchip Technology Inc.

5.0
Since the device will not acknowledge during a write
cycle, this can be used to determine when the cycle is
complete (this feature can be used to maximize bus
throughput). Once the Stop condition for a Write
command has been issued from the master, the device
initiates the internally timed write cycle. ACK polling
can be initiated immediately. This involves the master
sending a Start condition followed by the control byte
for a Write command (R/W = 0). If the device is still
busy with the write cycle, then no ACK will be returned.
If the cycle is complete, then the device will return the
ACK and the master can then proceed with the next
Read or Write command. See Figure 5-1 for the flow
diagram.
FIGURE 5-2:
© 2007 Microchip Technology Inc.
Bus Activity
Master
Bus Activity
SDA Line
VCLK
ACKNOWLEDGE POLLING
S
T
A
R
T
S
PAGE WRITE
Control
Byte
A
C
K
Address
Word
A
C
K
Data (n)
FIGURE 5-1:
A
C
K
Initiate Write Cycle
Send Control Byte
Data n + 1
Write Command
Acknowledge
with R/W = 0
Condition to
(ACK = 0)?
Did Device
Send Stop
Send Start
Operation
Send
Next
ACKNOWLEDGE
POLLING FLOW
Yes
24LCS21A
A
C
K
No
Data n + 7
DS21161H-page 11
A
C
K
S
O
P
T
P