Datasheet

 2012 Microchip Technology Inc. Preliminary DS22292A-page 17
MCP7940M
5.2.2.3 Sequential Read
Sequential reads are initiated in the same way as a
random read except that after the MCP7940M
transmits the first data byte, the master issues an
Acknowledge as opposed to the Stop condition used in
a random read. This Acknowledge directs the
MCP7940M to transmit the next sequentially
addressed 8-bit word (Figure 5-6). Following the final
byte transmitted to the master, the master will NOT
generate an Acknowledge but will generate a Stop
condition. To provide sequential reads, the MCP7940M
contains an internal Address Pointer which is
incremented by one at the completion of each
operation. This Address Pointer allows the entire
memory contents to be serially read during one
operation. The internal Address Pointer will automat-
ically roll over to the start of the Block.
FIGURE 5-5: RANDOM READ
FIGURE 5-6: SEQUENTIAL READ
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
A
C
K
N
O
A
C
K
A
C
K
A
C
K
S
T
O
P
S
T
A
R
T
CONTROL
BYTE
ADDRESS
BYTE
CONTROL
BYTE
DATA
BYTE
S
T
A
R
T
S
1101 0
111
S 1010 1 P
BUS ACTIVITY
MASTER
SDA LINE
BUS ACTIVITY
CONTROL
BYTE
DATA n DATA n + 1 DATA n + 2 DATA n + X
N
O
A
C
K
A
C
K
A
C
K
A
C
K
A
C
K
S
T
O
P
P