ST72681 STMicroelectronics, ST72681 Datasheet - Page 21

• Manufacturer Part Number: ST72681
• Description: USB 2.0 HIGH-SPEED 8-BIT MCU FLASH DRIVE CONTROLLER
• Manufacturer: STMicroelectronics

ST72681
7.5.2
Table 13.
1. Data based on typical application software.
2. Time measured between interrupt event and interrupt vector fetch. Δt
Crystal oscillator
The ST72681 internal clock is supplied from a crystal oscillator. All the information given in
this paragraph are based on characterization results with specified typical external
components. In the application the load capacitors have to be placed as close as possible to
the oscillator pins in order to minimize output distortion and start-up stabilization time. Refer
to the crystal manufacturer for more details (frequency, package, accuracy...).
Table 14.
1. The crystal oscillator duty cycle has to be adjusted through the two C
Figure 7.
1. Depending on the crystal oscillator power dissipation, a serial resistor R
Table 15.
f
CK
α
Symbol
Symbol
OSC
OSC
t
v(IT)
required to finish executing the current instruction.
manufacturer for more details.
crystal oscillator manufacturer for more details.
ACC
Interrupt reaction time
t
v(IT)
Oscillator frequency
Total crystal oscillator accuracy abs. value + temp + aging
Crystal oscillator duty cycle
V
DDA
General timing characteristics (continued)
Crystal oscillator characteristics
Typical application with a crystal oscillator
Typical C
Supplier
= Δt
NDK
c(INST)
Parameter
Parameter
C
C
L
L
L
+ 10
and R
(2)
S
CRYSTAL
values by crystal oscillator
R
sOscout
(1)
Typical crystal oscillator
f
(1)
CPU
AT51 or AT41
= 12 MHz
Conditions
OSCIN
OSCOUT
Conditions
c(INST)
L
capacitors. Refer to the crystal
sOscout
0.666
Min.
10
is the number of t
Electrical characteristics
C
Min.
may be added. Refer to the
45
L
16
Typ.
(pF)
Device
Typ.
(1)
12
50
1.466
Max.
CPU
22
R
Max.
±60
55
sOscout
cycles
560
Unit
t
MHz
Unit
ppm
CPU
21/34
µs
(Ω)
%