MC68HC705JP7 Datasheet, PDF (129/242 Pages) Motorola, Inc – HCMOS Microcontroller Unit

Freescale Semiconductor, Inc.
Analog Subsystem
A/D Conversion Methods
V_CAP
V_X
t_DIS
t_DIS
(MIN)
t_DIS
(MIN)
V_MAX
t_CHG
V_X = ^{tCHG x ICHG}
C_EXT
CHG
COMP2
TOF
OCF
ICF
0
1
2
31
2
Point
Action
Software/Hardware Action
Begin initial discharge and select
0 mode 1 by clearing CHG and ATD2 Software write
and setting ATD1 in the ACR.
1 V_CAP falls to V_SS.
Wait out minimum t_DIS time.
2
Stop discharge and begin charge by
setting CHG control bit in ACR.
Software write
V_CAP rises to V_X and comparator 2
3
output trips, setting CPF2 and
CMP2, which clears CHG control bit
in the ACR. Reset CPF2 by writing a
Wait out t_CHG time.
CPF2 clears CHG control bit.
1 to CPFR2.
Dependent Variable(s)
Software
V_MAX, I_DIS, C_EXT
Software
V_X, I_CHG, C_EXT
Figure 8-9. A/D Conversion — Manual/Auto Discharge Control (Mode 1)
MC68HC705JJ7 • MC68HC705JP7 — REV 4
MOTOROLA
Analog Subsystem
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Advance Information
129