ST10F272B_12 STMICROELECTRONICS [STMicroelectronics], ST10F272B_12 Datasheet - Page 156

• Manufacturer Part Number: ST10F272B_12
• Description: 16-bit MCU with 256 Kbyte Flash memory and 12/20 Kbyte RAM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

Electrical characteristics
Table 70.
24.8.9
156/188
1
1
1
1
0
0
0
0
(P0H.7-5)
P0.15-13
1
1
0
0
1
1
0
0
1
0
1
0
1
0
1
0
Internal PLL divider mechanism
The PLL input frequency range is limited to 1 to 3.5MHz, while the VCO oscillation range is
64 to 128MHz. The CPU clock frequency range when PLL is used is 16 to 64MHz.
Example 1
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Example 2
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PLL Jitter
The following terminology is hereafter defined:
●
●
5.3 to 10.6MHz
6.4 to 12MHz
4 to 12MHz
4 to 6.4MHz
Frequency
1 to 64MHz
4 to 8MHz
4 to 8MHz
F
P0(15:13) = ‘110’ (Multiplication by 3)
PLL Input Frequency = 1MHz
VCO frequency = 48MHz
PLL Output Frequency = 12MHz
(VCO frequency divided by 4)
F
F
P0(15:13) = ‘100’ (Multiplication by 5)
PLL Input Frequency = 2MHz
VCO frequency = 80MHz
PLL Output Frequency = 40MHz (VCO frequency divided by 2)
F
Self referred single period jitter
Also called “Period Jitter”, it can be defined as the difference of the T
where T
time period of the PLL output clock.
Self referred long term jitter
Also called “N period jitter”, it can be defined as the difference of T
T
minimum time difference between N+1 clock rising edges. Here N should be kept
XTAL
CPU
XTAL
CPU
max
4MHz
XTAL
is the maximum time difference between N+1 clock rising edges and T
= 12MHz (no effect of Output Prescaler)
= 40MHz (no effect of Output Prescaler)
= 4MHz
= 8MHz
max
1)
1)
1)
is maximum time period of the PLL output clock and T
Prescaler
F
F
F
F
F
F
XTAL
XTAL
XTAL
XTAL
XTAL
XTAL
Input
–
–
/ 4
/ 4
/ 4
/ 4
/ 2
/ 2
Doc ID 11917 Rev 3
Multiply by
64
48
64
40
40
64
PLL bypassed
PLL bypassed
PLL
Divide by
4
4
2
2
2
2
Prescaler
F
Output
PLL
–
–
–
–
–
–
–
/ 2
ST10F272B/ST10F272E
max
min
max
CPU Frequency
f
is the minimum
and T
CPU
F
F
and T
F
F
F
F
F
F
XTAL
XTAL
XTAL
XTAL
XTAL
XTAL
XTAL
= f
XTAL
min
min
XTAL
x 10
x 16
x 4
x 3
x 8
x 5
x 1
min
/ 2
, where
is the
x F
,