SMD1108
Preliminary
The SMD1108 automatically increments the address for
subsequentdatawords. Afterthereceiptofeachwordthe
low order address bits are internally incremented by one.
The high order bits of the address byte remain constant.
Should the Master transmit more than 16 bytes, prior to
generating the Stop condition, the address counter will
rollover, and the previously written data will be overwrit-
ten. As with the byte Write operation all inputs are
disabled during the internal write cycle. Refer to Figure
2 for the address, Acknowledge, and data transfer se-
quence.
Write Cycle
In Progress
Issue Start
Issue Stop
Issue Slave
Address and
R/W = 0
Acknowledge Polling
No
ACK
When the SMD1108 is performing an internal Write
operationitwillignoreanynewStartconditions. Sincethe
device will only return an acknowledge after it accepts the
Start, the part can be continuously queried until an
acknowledge is issued, indicating that the internal Write
cycle is complete. See the flow diagram (Figure 3) for the
proper sequence of operations for polling.
Returned
Yes
Next
Operation
a Write?
No
Yes
READ OPERATIONS
Issue Stop
Issue
Address
Read operations are initiated with the R/W bit of the
identification field set to 1. There are two different Read
options: (1) Current Address Byte Read; or (2) Random
Address Byte Read
Proceed
With
Write
Await
Next
Command
Current Address Read
TheSMD1108containsaninternaladdresscounterwhich
maintains the address of the last word accessed, incre-
2052 Fig03
Figure 3. Polling Sequence
S
T
A
R
T
S
T
O
P
Typical Write Operation
Master
SDA
R
/
W
A A A
2 1
A A A A A A A A
7 6
D D D D D D D D
D D
D D
1 0
0
5
4
3
2
1
0
7
6
5
4
3
2
1
0
7
6
A
C
K
A
C
K
A
C
K
A
C
K
Slave
S
T
A
R
T
Typical Read Operation
S
T
O
P
N
A
C
K
A
C
K
A
C
K
Master
SDA
R
/
W
A A A
2 1
D D D D D D D D
D D D D D D D D
D D
D D
1 0
0
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
7
6
A
C
K
Slave
2052 Fig02 2.0
Figure 2. Address, Acknowledge and Data Transfer Sequence
2052 2.0 10/05/01
SUMMIT MICROELECTRONICS, Inc.
10
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
