XC68HC705JJ7 Motorola, XC68HC705JJ7 Datasheet - Page 131

• Manufacturer Part Number: XC68HC705JJ7
• Description: MICROCONTROLLER
• Manufacturer: Motorola

MC68HC705JJ7 • MC68HC705JP7 — REV 4
MOTOROLA
Point
0
1
2
3
Begin initial discharge and select mode 3
by clearing CHG and setting ATD2 and
ATD1 in the ACR. Also set ICEN bit in
ACR and IEDG bit in TCR.
V
compare registers (OCRH and OCRL) to
desired charge start time.
Stop discharge and begin charge when
the next OCF sets the CHG control bit in
ACR.
V
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 flag. Load
next OCF.
COMP2
CAP
CAP
(TCAP)
V
CHG
OCF
TOF
CAP
ICF
V
X
falls to V
rises to V
Figure 8-11. A/D Conversion — OCF/ICF Control (Mode 3)
0
SS
X
Action
. Set timer output
and comparator 2
1
(MIN)
t
t
DIS
DIS
2
Analog Subsystem
t
CHG
Software write
Wait out minimum t
Software write to OCRH, OCRL
Timer OCF sets the CHG control
bit in the ACR.
Wait out t
Timer ICF clears the CHG control
bit in the ACR.
Software/Hardware Action
CHG
3
time.
1
(MIN)
t
DIS
DIS
time.
2
Software
V
software
Free-running timer
output compare, f
V
Dependent Variable(s)
A/D Conversion Methods
V
MAX
X
V
MAX
, I
X
=
CHG
, I
Advance Information
t
CHG
DIS
Analog Subsystem
C
, C
EXT
x I
, C
EXT
CHG
EXT
,
OSC
131