Analog Devices ADuC812 - Manual (Page 46)

REV. B
ADuC812
–46–
(AV
DD
= DV
DD
= 3.0 V or 5.0 V ؎ 10%. All specifications T
A
= T
MIN
to T
MAX
unless otherwise noted.)
12 MHz Variable Clock
Parameter Min Typ Max Min Typ Max Unit Figure
CLOCK INPUT (External Clock Driven XTAL1)
t
CK
XTAL1 Period 83.33 62.5 1000 ns 50
t
CKL
XTAL1 Width Low 20 20 ns 50
t
CKH
XTAL1 Width High 20 20 ns 50
t
CKR
XTAL1 Rise Time 20 20 ns 50
t
CKF
XTAL1 Fall Time 20 20 ns 50
t
CYC
4 ADuC812 Machine Cycle Time 1 12t
CK
µs
NOTES
1 AC inputs during testing are driven at DV
DD
– 0.5 V for a Logic 1 and 0.45 V for a Logic 0. Timing measurements are made at V
IH
min for a Logic 1 and V
IL
max for
a Logic 0.
2 For timing purposes, a port pin is no longer floating when a 100 mV change from load voltage occurs. A port pin begins to float when a 100 mV change from the
loaded V
OH
/V
OL
level occurs.
3 C
LOAD
for Port0, ALE, PSEN outputs = 100 pF; C
LOAD
for all other outputs = 80 pF unless otherwise noted.
4 ADuC812 Machine Cycle Time is nominally defined as MCLKIN/12.
t
CKL
t
CKF
t
CK
t
CKH
t
CKR
Figure 49. XTAL 1 Input
DV DD – 0.5V
0.45V
0.2V CC + 0.9V
TEST POINTS
0.2V
CC – 0.1V
V LOAD – 0.1V
V
LOAD
V
LOAD
+ 0.1V
TIMING
REFERENCE
POINTS
V LOAD – 0.1V
V
LOAD
V LOAD – 0.1V
Figure 50. Timing Waveform Characteristics
TIMING SPECIFICATIONS
1, 2, 3