GENERAL RELEASE SPECIFICATION
August 27, 1998
t
DIS
t
t
DIS
DIS
(MIN)
(MIN)
V
CAP
V
MAX
t
CHG
t
X I
CHG
CHG
V
V
=
X
X
C
X
CHG
COMP
(TCAP)
TOF
OCF
ICF
0
1
2
3
1
3
Point
Action
Software/Hardware Action
Dependent Variable(s)
Begin initial Discharge and select
Mode 3 by clearing CHG and set-
ting ATD2 and ATD1 in the ACR.
Software write.
(ICEN bit also set)
0
Software.
V
falls to V . Set Timer output
SS
CAP
Wait out minimum t
Software write to OCRH, OCRL.
time.
DIS
1
2
compare registers (OCRU, OCRL)
to desired charge start time.
V
, I , C , Software.
MAX DIS X
Stop Discharge and begin Charge
when the next OCF sets the CHG
control bit in ACR.
Timer OCF sets the CHG control bit Free-running Timer
in the ACR. counter overflow, f
, P.
OSC
V
rises to V and comparator
X
CAP
Wait out t
Timer ICF clears the CHG control
bit in the ACR.
time.
CHG
output trips, setting CPF which
causes an ICF from the Timer and
clears the CHG control bit in ACR.
3
V , I
, C
X
CHG X.
Figure 15-11. A/D Conversion - OCF/ICF Control (Mode 3)
MOTOROLA
15-26
ANALOG SUBSYSTEM
MC68HC05SB7
REV 2.1
FREESCALE [ Freescale ]
