M65KA128AL Datasheet, PDF (20/53 Pages) STMicroelectronics – 128Mbit (4 Banks x 2M x 16) 1.8V Supply, Low Power SDRAMs

Register descriptions
5
Register descriptions
M65KA128AL
5.1
Mode Register description
The Mode Register is used to select the CAS Latency (1, 2 or 3), the Burst Type (sequential,
interleaved), and the Burst Length (1-, 2-, 4-, 8-Word width or full page).
It is loaded by issuing a Mode Register Set command that programs A0 to A11 address bits.
The values placed on the address lines are then latched into the Mode Register. BA0-BA1
must be set to ‘0’.
See Table 4: Mode Register Definition, for more details.
Table 4. Mode Register Definition
Address
Bits
Mode
Register Bit
Register
Description
Value
Bit Description
A11-A7
-
-
00000
010
2 Clock Cycles
A6-A4
MR6-MR4
CAS Latency Bits 011
3 Clock Cycles
Other configurations reserved
0
A3
MR3
Burst Type
1
Sequential
Interleaved
000
1 Word (A3 is Don’t Care)
001
2 Words (A3 is Don’t Care)
A2-A0
MR2-MR0
010
Burst Length Bit ₀₁₁
4 Words (A3 is Don’t Care)
8 Words (A3 is Don’t Care)
Full Page if A3 Low
111
Reserved if A3 High
Other configurations reserved
BA1-BA0
-
-
00
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