SMS8198
WRITE OPERATIONS
While the internal write cycle is in progress, theSMS8198
inputs are disabled, and the device will not respond to any
The SMS8198 allows two types of write operations: byte requests from the master. Refer to Figure 6 for the
write and page write. The byte write operation writes a address, ACKnowledge and data transfer sequence.
single byte during the nonvolatile write period (tWR). The
Page WRITE
page write operation allows up to 16 bytes in the same
The SMS8198 is capable of a 16-byte page write opera-
page to be written during tWR
.
tion. It is initiated in the same manner as the byte-write
operation, but instead of terminating the write cycle after
Byte WRITE
After the slave address is sent (to identify the slave the first data word, the master can transmit up to 15 more
device, specify high order word address and a read or words of data. After the receipt of each word, the
write operation), a second byte is transmitted which SMS8198 will respond with an ACKnowledge.
contains the low 8 bit addresses of any one of the 2,048
The SMS8198 automatically increments the address for
words in the array.
subsequent data words. After the receipt of each word,
Upon receipt of the word address, the SMS8198 re- the four low order address bits are internally incremented
sponds with an ACKnowledge. After receiving the next byone. Thehighorderfivebitsoftheaddressbyteremain
byteofdata,itagainrespondswithanACKnowledge.The constant. Should the master transmit more than sixteen
master then terminates the transfer by generating a words, prior to generating the STOP condition, the ad-
STOP condition, at which time the SMS8198 begins the dress counter will “roll over,” and the previously written
internal write cycle.
data will be overwritten. As with the byte-write operation,
all inputs are disabled during the internal write cycle.
Refer to Figure 6 for the address, ACKnowledge and data
transfer sequence.
If single byte-write only,
Stop bit issued here.
Acknowledges Transmitted from
SMS8198 to Master Receiver
Acknowledges Transmitted from
SMS8198 to Master Receiver
A
C
K
A
C
K
A
C
K
A
C
K
A
C
K
SDA
Bus
A
10
A
9
A
8
R
W
Word Address
Data Byte n
Data Byte n+1
Data Byte n+15
Activity
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
D
7
D
6
D
5
D
4
D
3
D
2
D
1
D
0
D
7
D
6
D
5
D
4
D
3
D
2
D
1
D
0
D
7
D
6
D
5
D
4
D
3
D
2
D
1
D
0
1 0 1 0
0
S
T
O
P
S
T
A
R
T
Device
Type
Address
A10,A9,A8
Read/Write
0= Write
Slave Address
Master Sends Read
Request to Slave
Master Writes Word
Address to Slave
Master Writes
Data to Slave
Master Writes
Data to Slave
Master Writes
Data to Slave
Master Transmitter
to
Master Transmitter
to
Master Transmitter
to
Master Transmitter
to
Master Transmitter
to
Slave Receiver
Slave Receiver
Slave Receiver
Slave Receiver
Slave Receiver
Slave Transmitter
to
Slave Transmitter
to
Slave Transmitter
to
Slave Transmitter
to
Slave Transmitter
to
Master Receiver
Master Receiver
Master Receiver
Master Receiver
Master Receiver
2036 ILL8.0
Shading Denotes
SMS8198
SDA Output Active
Figure 6. Page/Byte WRITE Mode
2036 5.0 4/18/00
7
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
