MC68HC05JJ6 Datasheet, PDF (126/216 Pages) Freescale Semiconductor, Inc – General Release Specification 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
(TCAP)
TOF
OCF
ICF
0
1
2
31
2
Point
Action
Software/Hardware Action
Begin initial discharge and select mode
0
2 by clearing CHG and ATD1 and
setting ATD2 in the ACR. Also set
Software write
ICEN bit in ACR and IEDG bit in TCR.
1 V_CAP falls to V_SS.
Wait out minimum t_DIS time.
2
Stop discharge and begin charge when
the next TOF sets the CHG control bit
in ACR.
Timer TOF sets the CHG control
bit in the ACR.
V_CAP rises to V_X and comparator 2
3
output trips, setting CPF2 and CMP2,
which causes an ICF from the timer
and clears the CHG control bit in ACR.
Must clear CPF2 to trap next CPF2
Wait out t_CHG time.
Timer ICF clears the CHG
control bit in the ACR.
flag.
Dependent Variable(s)
Software
V_MAX, I_DIS, C_EXT
Free-running timer
counter overflow, f_OSC
V_X, I_CHG, C_EXT
Figure 8-10. A/D Conversion — TOF/ICF Control (Mode 2)
General Release Specification
126
Analog Subsystem
MC68HC05JJ6/MC68HC05JP6 — Rev. 3.2
Freescale Semiconductor