ST10 STMICROELECTRONICS [STMicroelectronics], ST10 Datasheet - Page 42

• Manufacturer Part Number: ST10
• Description: 16-BIT MCU WITH 32K BYTE ROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST10C167
XX - ELECTRICAL CHARACTERISTICS (continued)
XX.4.1 - Definition of internal timing
The internal operation of the ST10C167 is
controlled by the internal CPU clock f
edges of the CPU clock can trigger internal (e.g.
pipeline) or external (e.g. bus cycles) operations.
The specification of the external timing (AC
Characteristics) therefore depends on the time
between two consecutive edges of the CPU clock,
called “TCL” periods (see Figure 11).
The CPU clock signal can be generated by
different mechanisms. The duration of TCL
periods and their variation (and also the derived
external timing) depends on the mechanism used
Figure 11 : Generation mechanisms for the CPU clock
Table 17 : CPU Frequency Generation
Notes 1. The external clock input range refers to a CPU clock range of 10...25MHz.
42/65
1
1
1
1
0
0
0
0
(P0H.7-5)
P0.15-13
2. The maximum frequency depends on the duty cycle of the external clock signal.
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
Phase locked loop operation
Direct Clock Drive
Prescaler Operation
CPU Frequency f
f
f
f
f
f
f
XTAL
CPU
XTAL
CPU
XTAL
CPU
F
F
F
F
F
F
F
F
XTAL
XTAL
XTAL
XTAL
XTAL
XTAL
XTAL
XTAL
x 1.5
x 2.5
CPU
x 4
x 3
x 2
x 5
x 1
/ 2
= f
CPU
XTAL
. Both
x F
External Clock Input Range
to generate f
when calculating the timings for the ST10C167.
The example for PLL operation shown in
Figure 11 refers to a PLL factor of 4.
The mechanism used to generate the CPU clock
is selected during reset by the logic levels on pins
P0.15-13 (P0H.7-5).
XX.4.2 - Clock generation modes
Table 18
combinations of these three bits with the
respective clock generation mode.
3.33 to 8.33MHz
6.66 to 16.6MHz
2.5 to 6.25MHz
5 to 12.5MHz
1 to 25MHz
2 to 50MHz
4 to 10MHz
2 to 5MHz
shows
CPU
TCL
. This influence must be regarded
TCL
the
TCL TCL
TCL TCL
1
association
Default configuration
Direct drive
CPU clock via prescaler
Notes
2
of
the