FM31T372/374/376/378-G
Start
S
No
Address
Acknowledge
Start
S
Address
By Master
Stop
Slave Address
0
A
Address MSB
A
Address LSB
Acknowledge
A
Slave Address
1
A
Data Byte
Data
1
P
By FM31xxx
By FM31T37x
Figure 16. Selective (Random) Memory Read
Address & Data
Start
S
Stop
By Master
Slave Address
0
A
Address
A
Data Byte
A
P
0 0 0
By FM31T37x
Acknowledge
Figure 17. Byte Register Write
NOTE: It is required that Register Address bits A7-A5 are cleared (zeroes).
Addressing F-RAM Array in the FM31T37x Family
The FM31T37x family includes 256Kb, 64Kb, 16Kb, and 4Kb memory densities. The following 2-byte address field
is shown for each density.
Table 4. Two-Byte Memory Address
Part #
FM31T378
1st Address Byte
2nd Address Byte
x
x
x
x
A14 A13 A12 A11 A10
A9
A9
A9
x
A8
A8
A8
A8
A7
A7
A7
A7
A6
A6
A6
A6
A5
A5
A5
A5
A4
A4
A4
A4
A3
A3
A3
A3
A2
A2
A2
A2
A1
A1
A1
A1
A0
A0
A0
A0
x
x
x
x
x
x
A12 A11 A10
FM31T376
FM31T374
FM31T372
x
x
x
x
A10
x
Rev. 1.1
Apr. 2011
Page 20 of 26
RAMTRON [ RAMTRON INTERNATIONAL CORPORATION ]
