Datasheet

Electrical Characteristics
MCF51AC256 ColdFire Microcontroller Data Sheet, Rev.7
Freescale Semiconductor 31
2.9 External Oscillator (XOSC) Characteristics
3
Monotonicity and No-Missing-Codes guaranteed in 10-bit and 8-bit modes
4
Based on input pad leakage current. Refer to pad electricals.
Table 15. Oscillator Electrical Specifications (Temperature Range = –40 to 105 C Ambient)
Num C Rating Symbol Min Typical
1
1
Data in Typical column was characterized at 5.0 V, 25 C or is typical recommended value.
Max Unit
1C
Oscillator crystal or resonator (EREFS = 1, ERCLKEN = 1)
Low range (RANGE = 0)
High range (RANGE = 1) FEE or FBE mode
2
High range (RANGE = 1) PEE or PBE mode
3
High range (RANGE = 1, HGO = 1) BLPE mode
High range (RANGE = 1, HGO = 0) BLPE mode
2
When MCG is configured for FEE or FBE mode, input clock source must be divisible using RDIV to within the range of
31.25 kHz to 39.0625 kHz.
3
When MCG is configured for PEE or PBE mode, input clock source must be divisible using RDIV to within the range of 1 MHz
to 2 MHz.
f
lo
f
hi-fll
f
hi-pll
f
hi-hgo
f
hi-lp
32
1
1
1
1
—
—
—
—
—
38.4
5
16
16
8
kHz
MHz
MHz
MHz
MHz
2 — Load capacitors
C
1
C
2
See crystal or resonator
manufacturer’s recommendation.
3—
Feedback resistor
Low range (32 kHz to 38.4 kHz)
High range (1 MHz to 16 MHz)
R
F
10
1
M
4—
Series resistor
Low range, low gain (RANGE = 0, HGO = 0)
Low range, high gain (RANGE = 0, HGO = 1)
High range, low gain (RANGE = 1, HGO = 0)
High range, high gain (RANGE = 1, HGO = 1)
 8 MHz
 MHz
 MHz
R
S
—
—
—
—
—
—
0
100
0
0
0
0
—
—
—
0
10
20
k
5T
Crystal start-up time
4
Low range, low gain (RANGE = 0, HGO = 0)
Low range, high gain (RANGE = 0, HGO = 1)
High range, low gain (RANGE = 1, HGO = 0)
5
High range, high gain (RANGE = 1, HGO = 1)
5
4
This parameter is characterized and not tested on each device. Proper PC board layout procedures must be followed to
achieve specifications.
5
4 MHz crystal
t
CSTL-LP
t
CSTL-HGO
t
CSTH-LP
t
CSTH-HGO
—
—
—
—
200
400
5
15
—
—
—
—
ms
6T
Square wave input clock frequency (EREFS = 0, ERCLKEN =
1)
FEE or FBE mode
2
PEE or PBE mode
3
BLPE mode
f
extal
0.03125
1
0
—
—
—
5
16
40
MHz