EDJ1108BABG, EDJ1116BABG
Write Timing Violations
Motivation
Generally, if timing parameters are violated, a complete reset/initialization procedure has to be initiated to make sure
the DRAM works properly.
However it is desirable for certain minor violations, that the DRAM is guaranteed not to "hang up" and error to be
limited to that particular operation.
For the following it will be assumed that there are no timing violations w.r.t to the write command itself (including
ODT etc.) and that it does satisfy all timing requirements not mentioned below.
Data Setup and Hold Violations
Should the data to strobe timing requirements (tDS, tDH) be violated, for any of the strobe edges associated with a
write burst, then wrong data might be written to the memory location addressed with this write command.
In the example (Figure Write Timing Parameters) the relevant strobe edges for write burst A are associated with the
clock edges: T5, T5.5, T6, T6.5, T7, T7.5, T8, T8.5.
Subsequent reads from that location might result in unpredictable read data, however the DRAM will work properly
otherwise.
Strobe to Strobe and Strobe to Clock Violations
Should the strobe timing requirements (tDQSH, tDQSL, tWPRE, tWPST) or the strobe to clock timing requirements
(tDSS, tDSH tDQSS) be violated for any of the strobe edges associated with a write burst, then wrong data might be
written to the memory location addressed with the offending write command. Subsequent reads from that location
might result in unpredictable read data, however the DRAM will work properly otherwise.
In the example (Figure Write Timing Parameters) the relevant strobe edges for write burst A are associated with the
clock edges: T4, T4.5, T5, T5.5, T6, T6.5, T7, T7.5, T8, T8.5 and T9. Any timing requirements starting and ending
on one of these strobe edges are T8, T8.5, T9, T9.5, T10, T10.5, T11, T11.5, T12, T12.5 and T13. Some edges are
associated with both bursts.
T0
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
T13 T14
CK
/CK
Command*3
WRIT
A
WRIT
B
NOP
NOP
Address*4
/CS
ODTL
BL/2 + 2 + ODTL
WL
tDQSS
tDSS
tDSH
tDQSL
tWPST
tWPRE
tDQSH
DQS, /DQS
DQ*2
tDH
tDS
VIH or VIL
Write Timing Parameters
Data Sheet E1248E40 (Ver. 4.0)
116
ELPIDA [ ELPIDA MEMORY ]
