Figure 14. C6201/C6202/C6203/C6204/C6205 Vs. C6201B/C6701 Output Timing; Figure 15. C621X/C671X/C64X Output Timing; C6000 Clock-To-Output Relationship - Texas Instruments TMS320C6000 Application Report

SPRA433E
2.4.4

C6000 Clock-to-Output Relationship

To optimize the synchronous memory interfaces of the various C6000 devices, the output
signals are triggered off of different internal clocks of the C6000 DSP. Figure 14 and Figure 15
show the clock relationship used for the various C6000 DSPs. Because the C621x/C671x/C64x
SDRAM interface is timed in reference to an externally provided clock, the C621x,C671x, and
C64x data sheets provide t
and t parameters use a factor of P in the equations allows the user to be unconcerned about
oh
the output edge being used internally to the C6000. In this way, the t
compared directly against the t
The t and t
dmax dmin
driven out. The t
osu
for the C621x,C671x, and C64x. The t
clock. The t term shows the hold time from the rising edge of the memory clock. P refers to the
oh
CPU clock period.
Notice that the data sheet notation directly implies the clocking relationship of the device. For
example, the data sheet for the C6201B SDRAM interface states that t
Referring to the diagram in Figure 14, it can be seen that t
rising edge of SDCLK, providing a setup time of 1.5P – t
be analyzed in the same way.
SDCLK
C6201/C6202
C6203/C6204
C6205
C6201B/C6701

Figure 14. C6201/C6202/C6203/C6204/C6205 vs. C6201B/C6701 Output Timing

Figure 15 shows the clock relationship used for the C621x/C671x/C64x SDRAM interface.
Because this interface is timed in reference to an externally provided clock, the C621x/C671x,
and C64x data sheets provide t
ECLKOUTx
C6211/C6711/C64xC
26 TMS320C6000 EMIF-to-External SDRAM Interface
and t , but not t
dmax dmin
parameter of the memory at a given operating speed.
isu
parameters reference the actual clock edge of the C6000 from which data is
and t terms are the notation used in the C6000 data sheets, except those
oh
term shows the setup time to the rising edge of the
osu
1/2 P 1/2 P
P P
t dmax
t osu = 1.5P − t dmax
t dmax
and t
dmax dmin
E E
t dmax

Figure 15. C621x/C671x/C64x Output Timing

and t , parameters. The fact that the t
osu oh
osu
is relative to a point ½ P from the
dmax
. All other C6000 data sheets can
dmax
P P P P
t osu = P − t dmax
t oh = F + t dmin
t osu = 0.5P − t dmax
t dmin
but not t and t parameters.
osu oh
E E
t dmin
osu
parameter can be
= 1.5P – 3.5 ns.
osu
P P
t dmin