ST72521 STMICROELECTRONICS [STMicroelectronics], ST72521 Datasheet - Page 172

• Manufacturer Part Number: ST72521
• Description: 8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC, FIVE TIMERS, SPI, SCI, I2C, CAN INTERFACE
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST72521
12.5 CLOCK AND TIMING CHARACTERISTICS
Subject to general operating conditions for V
12.5.1 General Timings
12.5.2 External Clock Source
Figure 89. Typical Application with an External Clock Source
Notes:
1. Data based on typical application software.
2. Time measured between interrupt event and interrupt vector fetch. t
the current instruction execution.
3. Data based on design simulation and/or technology characteristics, not tested in production.
172/211
t
t
Symbol
Symbol
w(OSC1H)
V
w(OSC1L)
V
t
t
t
r(OSC1)
f(OSC1)
c(INST)
OSC1H
OSC1L
t
v(IT)
I
L
V
V
Instruction cycle time
Interrupt reaction time
t
OSC1 input pin high level voltage
OSC1 input pin low level voltage
OSC1 high or low time
OSC1 rise or fall time
OSCx Input leakage current
OSC1H
OSC1L
v(IT)
EXTERNAL
CLOCK SOURCE
= t
c(INST)
Parameter
Parameter
+ 10
t
r(OSC1)
3)
2)
3)
t
f(OSC1)
OSC2
OSC1
90%
f
f
see
V
DD
CPU
CPU
SS
10%
, f
Figure 89
=8MHz
=8MHz
V
CPU
IN
Conditions
Conditions
, and T
V
DD
t
Not connected internally
w(OSC1H)
A
.
c(INST)
I
is the number of t
L
t
w(OSC1L)
1.25
Min
250
10
V
2
Min
V
DD
5
SS
-1
f
OSC
Typ
ST72XXX
375
3
Typ
CPU
1)
cycles needed to finish
1500
Max
2.75
V
Max
12
22
V
SS
15
±1
DD
+1
Unit
Unit
t
t
CPU
CPU
ns
ns
V
A
s