Texas Instruments TMS320 - Manual (Page 36)

TMS320C25 50
SPRS010B — MAY 1987 — REVISED NOVEMBER 1990
POST OFFICE BOX 1443

HOUSTON, TEXAS 77001 36
+5 V
f
crystal
4.7 k
10 k
74HC04
F11
CLKIN
47 pF
74AS04
10 k
C = 20 pF 0.1 F
L
TMS320C25
TMS320C25
TMS320C25-50
TMS320E25 40.96
51.20
40.96 1.8
1.0
1.8
f
crystal,
(MHz) L, (H)
Figure 7. External Clock Option
timing requirements over recommended operating conditions (see Note 3)
MIN NOM MAX UNIT
t
c(CI)
CLKIN cycle time
19.5
3
150 ns
t
f(CI)
CLKIN fall time 5 † ns
t
r(CI)
CLKIN rise time 5 † ns
t
w(CIL)
CLKIN low pulse duration, t
c(CI)
= 50 ns (see Note 4) 20 ns
t
w(CIH)
CLKIN high pulse duration, t
c(CI)
= 50 ns (see Note 4) 20 ns
t
su(S)
SYNC setup time before CLKIN low 4 Q -- 4 ns
t
h(S)
SYNC hold time from CLKIN low 4 ns
† Value derived from characterization data and not tested.
NOTES: 3. Q = 1/4 t
c(C)
4. CLKIN duty cycle [t
r(CI)
+ t
w(CIH)
]/t
c(CI)
must be within 40-60%.
ADV
ANCE
INFORMA
T
ION