Harman Kardon AVR 254, Service Manual

Page: 109 / 189

12
Revision 1.9
256M Double Data Rate Synchronous DRAM
A3S56D30ETP
A3S56D40ETP
FUNCTION TRUTH TABLE (continued)
Current State /CS /RAS /CAS /WE Address Command Action Notes
REFRESHING H X X X X DESEL NOP (Idle after tRC)
L H H H X NOP NOP (Idle after tRC)
L H H L BA TERM ILLEGAL
L H L X BA, CA, A10 READ / WRITE ILLEGAL
L L H H BA, RA ACT ILLEGAL
L L H L BA, A10 PRE / PREA ILLEGAL
L L L H X REFA ILLEGAL
L L L L
Op-Code, Mode-
Add
MRS ILLEGAL
H X X X X DESEL NOP (Row Active after tRSC)
L H H H X NOP NOP (Row Active after tRSC)
L H H L BA TERM ILLEGAL
L H L X BA, CA, A10 READ / WRITE ILLEGAL
L L H H BA, RA ACT ILLEGAL
L L H L BA, A10 PRE / PREA ILLEGAL
L L L H X REFA ILLEGAL
L L L L
Op-Code, Mode-
Add
MRS ILLEGAL
MODE
REGISTER
SETTING
ABBREVIATIONS:
H=High Level, L=Low Level, X=Don't Care
BA=Bank Address, RA=Row Address, CA=Column Address, NOP=No Operation
NOTES:
1. All entries assume that CKE was High during the preceding clock cycle and the current clock cycle.
2. ILLEGAL to bank in specified state; function may be legal in the bank indicated by BA, depending on the state of
that bank.
3. Must satisfy bus contention, bus turn around, write recovery requirements.
4. NOP to bank precharging or in idle state. May precharge bank indicated by BA.
5. ILLEGAL if any bank is not idle.
ILLEGAL = Device operation and/or data-integrity are not guaranteed.
109
AVR254
harman/kardon