mpc5125 Freescale Semiconductor, Inc, mpc5125 Datasheet - Page 44

• Manufacturer Part Number: mpc5125
• Description: Mpc5125 Microcontroller Data Sheet
• Manufacturer: Freescale Semiconductor, Inc

Electrical and Thermal Characteristics
4.2.1
The system oscillator can work in oscillator mode or in bypass mode to support an external input clock as clock reference.
NOTES:
1
2
3
4
5
4.2.2
44
SYS_XTAL frequency
RTC_XTAL frequency
The SYS_XTALI frequency and system PLL settings must be chosen such that the resulting system frequencies do not exceed
their respective maximum or minimum operating frequencies. See the MPC5125 Reference Manual (MPC5125RM).
The min/max cycle times are calculated using 1/f
Table 12
Rise time is measured from 20% of VDD to 80% of VDD.
Fall time is measured from 20% of VDD to 80% of VDD.
SYS_XTALI duty cycle is measured at V
t
•
•
t
CYCLE
Sym
t
t
DUTY
RISE
FALL
SYS_XTAL_I CLK
The system PLL (SYS_PLL) takes an external reference frequency and generates the internal system clock. The
system clock frequency is determined by the external reference frequency and the settings of the SYS_PLL
configuration.
The e300 core PLL (CORE_PLL) generates a master clock for all of the CPU circuitry. The e300 core clock frequency
is determined by the system clock frequency and the settings of the CORE_PLL configuration.
Characteristic
Characteristic
(system oscillator electrical characteristics).
System Oscillator Electrical Characteristics
RTC Oscillator Electrical Characteristics
SYS_XTALI cycle time
SYS_XTALI rise time
SYS_XTALI fall time
SYS_XTALI duty cycle ( measured at V
Table 12. System Oscillator Electrical Characteristics
Table 14. RTC Oscillator Electrical Characteristics
4
3
V
Figure 4. Timing Diagram — SYS_XTAL_IN
1,2
M
MPC5125 Microcontroller Data Sheet, Rev. 3
f
t
f
sys_xtal
rtc_xtal
DUTY
Sym
Sym
M
.
Table 13. SYS_XTAL_IN Timing
Description
t
CYCLE
sys_xtal (MIN/MAX)
V
M
t
DUTY
M
)
15.6
Min
Min
5
—
V
M
where the f
Typical
Typical
32.768
33.3
t
RISE
sys_xtal (MIN/MAX)
CV
CV
IH
IL
Max
35.0
Max
—
64.1
Min
40
1
1
(15.6 / 35 MHz) are taken from
28.57
Max
60
4
4
Freescale Semiconductor
Unit
MHz
Unit
kHz
Units
ns
ns
ns
%
t
FALL
SpecID
SpecID
O1.1
O2.1
SpecID
O.1.2
O.1.3
O.1.4
O.1.5