GPMC
If GPMC_CONFIG6_i[6] CYCLE2CYCLEDIFFCSEN is enabled, the chip-select access is delayed until
CYCLE2CYCLEDELAY cycles have expired since the end of a previous access to a different chip-select.
CYCLE2CYCLEDELAY count starts at CSRDOFFTIME/CSWROFFTIME completion. All control signals
are kept inactive during the idle GPMC_FCLK cycles.
CYCLE2CYCLESAMECSEN and CYCLE2CYCLEDIFFCSEN should be set in registers to respectively get
idle cycles inserted between accesses on this chip-select and after accesses to a different chip-select.
The CYCLE2CYCLEDELAY delay runs in parallel with the BUSTURNAROUND delay. It should be noted
that BUSTURNAROUND is a timing parameter defined for the ending chip-select access, whereas
CYCLE2CYCLEDELAY is a timing parameter defined for the starting chip-select access. The effective
minimum delay between successive accesses is based on the larger delay timing parameter and on
access type combination, since bus turnaround does not apply to all access types. See
for more details on bus turnaround.
describes the configuration required for idle cycle insertion.
Table 7-10. Idle Cycle Insertion Configuration
BUSTURN
CYCLE2
CYCLE2
First
Second
Idle Cycle Insertion
AROUND
Addr/Data
CYCLE
CYCLE
Access
Access
Chip-Select
Between the Two
Timing
Multiplexed
SAMECSEN
DIFFCSEN
Type
Type
Accesses
Parameter
Parameter
Parameter
No idle cycles are inserted
R/W
0
R/W
Any
Any
0
x
if the two accesses are well
pipelined.
No idle cycles are inserted
R
>0
R
Same
Nonmuxed
x
0
if the two accesses are well
pipelined.
BUSTURNAROUND cycles
R
>0
R
Different
Nonmuxed
0
0
are inserted.
BUSTURNAROUND cycles
R
>0
R/W
Any
Muxed
0
0
are inserted.
BUSTURNAROUND cycles
R
>0
W
Any
Any
0
0
are inserted.
No idle cycles are inserted
W
>0
R/W
Any
Any
0
0
if the two accesses are well
pipelined.
CYCLE2CYCLEDELAY
R/W
0
R/W
Same
Any
1
x
cycles are inserted.
CYCLE2CYCLEDELAY
R/W
0
R/W
Different
Any
x
1
cycles are inserted.
CYCLE2CYCLEDELAY
cycles are inserted. If BTA
idle cycles already apply on
these two back-to-back
R/W
>0
R/W
Same
Any
1
x
accesses, the effective
delay is max
(BUSTURNAROUND,
CYCLE2CYCLEDELAY).
CYCLE2CYCLEDELAY
cycles are inserted. If BTA
idle cycles already apply on
these two back-to-back
R/W
>0
R/W
Different
Any
x
1
accesses, the effective
delay is maximum
(BUSTURNAROUND,
CYCLE2CYCLEDELAY).
273
SPRUH73H – October 2011 – Revised April 2013
Memory Subsystem
Copyright © 2011–2013, Texas Instruments Incorporated