. Upon receipt of
the slave address with R/W bit set to 鈥?/div>
1
鈥? the 24XX01
issues an acknowledge and transmits the 8-bit data
word. The master will not acknowledge the transfer but
does generate a Stop condition and the 24XX01
discontinues transmission (Figure 7-1).
7.4
Noise Protection
The 24XX01 employs a V
CC
threshold detector circuit
which disables the internal erase/write logic if the V
CC
is below 1.5V at nominal conditions.
The SCL and SDA inputs have Schmitt Trigger and
filter circuits which suppress noise spikes to assure
proper device operation even on a noisy bus.
7.2
Random Read
Random read operations allow the master to access
any memory location in a random manner. To perform
this type of read operation, the word address must first
be set. This is accomplished by sending the word
address to the 24XX01 as part of a write operation.
Once the word address is sent, the master generates a
Start condition following the acknowledge. This
terminates the write operation, but not before the inter-
nal address pointer is set. The master then issues the
control byte again, but with the R/W bit set to a 鈥?/div>
1
鈥? The
24XX01 will then issue an acknowledge and transmits
the 8-bit data word. The master will not acknowledge
the transfer but does generate a Stop condition and the
24XX01 discontinues transmission (Figure 7-2).
FIGURE 7-1:
CURRENT ADDRESS READ
BUS ACTIVITY
MASTER
S
T
A
R
T
S
A
C
K
N
O
C
K
A
CONTROL
BYTE
DATA (n)
S
T
O
P
P
SDA LINE
BUS ACTIVITY
铮?/div>
2003 Microchip Technology Inc.
DS21711C-page 9
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