MC68HC705JJ7 Datasheet, PDF (86/164 Pages) Freescale Semiconductor, Inc – Microcontrollers

Analog Subsystem
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
0
1
2
3
Action
Software/Hardware Action
Dependent Variable(s)
Begin initial discharge and select mode
1 by clearing CHG and ATD2 and setting Software write
ATD1 in the ACR.
Software
V_CAP falls to V_SS.
Wait out minimum t_DIS time.
V_MAX, I_DIS, C_EXT
Stop discharge and begin charge by
setting CHG control bit in ACR.
Software write
Software
V_CAP rises to V_X and comparator 2
output trips, setting CPF2 and CMP2,
which clears CHG control bit in the ACR.
Reset CPF2 by writing a 1 to CPFR2.
Wait out t_CHG time.
CPF2 clears CHG control bit.
V_X, I_CHG, C_EXT
Figure 8-9. A/D Conversion — Manual/Auto Discharge Control (Mode 1)
MC68HC705JJ7 • MC68HC705JP7 Advance Information Data Sheet, Rev. 4.1
86
Freescale Semiconductor