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MC68HC705JJ7 Datasheet, PDF (84/164 Pages) Freescale Semiconductor, Inc – Microcontrollers
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Analog Subsystem
Table 8-4. A/D Conversion Parameters (Continued)
Name
P
fOSC
Function
Prescaler into timing function (÷ P)
Using core timer
Using 16-bit programmable timer
Using software loops
Clock source frequency (excluding any
prescaling)
1. Limited by requirement for CEXT to be less than 2.0 µF
Min
Typ
Max
8
8
8
8
8
8
24
User defined User defined
Refer to 15.11 Control Timing (5.0 Vdc)
and 15.12 Control Timing (3.0 Vdc)
Units
÷P
Table 8-5. Sample Conversion Timing (VDD = 5.0 Vdc)
Bits Counts
VX
(Vdc)
4
16
3.5
A/D Method
Software loop
(12 bus cycles)
(24 fOSC cycles)
Mode 0 or 1 (manual)
Clock Source
Low-power oscillator
External pin oscillator
Programmable timer
4
16
3.5
(prescaler = 8)
Mode 2 or 3
(TOF ≥ ICF or OCF ≥ ICF)
Low-power oscillator
External pin oscillator
6
64
3.5
Software loop
(12 bus cycles)
(24 fOSC cycles)
Mode 0 or 1 (manual)
Low-power oscillator
External pin oscillator
Programmable timer
6
64
3.5
(prescaler = 8)
Mode 2 or 3
(TOF ≥ CF or OCF ≥ ICF)
Low-power oscillator
External pin oscillator
8
256
3.5
Software loop
(12 bus cycles)
(24 fOSC cycles)
Mode 0 or 1 (manual)
Low-power oscillator
External pin oscillator
Programmable timer
8
256
3.5
(prescaler = 8)
Mode 2 or 3
(TOF ≥ CF or OCF ≥ ICF)
Low-power oscillator
External pin oscillator
Programmable timer
10 1024
3.5
(prescaler = 8)
Mode 2 or 3
(TOF ≥ ICF or OCF ≥ ICF)
Low-power oscillator
External pin oscillator
Programmable timer
12 4096
3.5
(prescaler = 8)
Mode 2 or 3
(TOF ≥ ICF or OCF ≥ ICF)
Low-power oscillator
External pin oscillator
1. Not usable as the value of CEXT would be greater than 2.0 µF
fOSC
(MHz)
0.1
1.0
2.0
4.0
0.1
1.0
2.0
4.0
0.1
1.0
2.0
4.0
0.1
1.0
2.0
4.0
0.1
1.0
2.0
4.0
0.1
1.0
2.0
4.0
0.1
1.0
2.0
4.0
0.1
1.0
2.0
4.0
tCHG
(ms)
3.840
0.384
0.192
0.096
1.280
0.128
0.064
0.032
15.36
1.536
0.768
0.384
5.120
0.512
0.256
0.128
61.44
6.144
3.072
1.536
20.48
2.048
1.024
0.512
Note 1
8.192
4.096
2.048
Note 1
32.768
16.384
8.192
CEXT (µF)
0.110
0.011
0.006
0.003
0.037
0.004
0.002
0.001
0.439
0.044
0.022
0.011
0.585
0.059
0.029
0.015
1.755
0.176
0.088
0.044
0.585
0.059
0.029
0.015
Note 1
0.234
0.117
0.059
Note 1
0.936
0.468
0.234
MC68HC705JJ7 • MC68HC705JP7 Advance Information Data Sheet, Rev. 4.1
84
Freescale Semiconductor
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