---------------------------------------------------------------------------HMCS404CL
Table 12. Timer Mode Register B
TMB
Bit
3
Auto-reload Function
o
No
Yes
TMB
Prescaler Divide Ratio,
Bit
2
Bit
1
Bit
0
Clock I
nput
Source
0
0 0
+2048
0 0
1
512
0 1 0
128
0 1 1
32
1
0
0
8
1
0
1
4
1 1
0
2
1 1
1
INTI
(External Event Input)
• TIMER-B
(TCBL:
$OOA,
TCBU:
$OOB)
TLRL:
$OOA,
TLRU:
$OOB
TIMER-B consists
of
an 8-bit write-only Timer Load Regis-
;er, and an 8-bit read-only Timer/Event Counter. Each
of
them
has a low-order digit (TCBL:
$OOA,
TLRL:
$OOA)
and a high-
order digit (TCBU:
$OOB,
TLRU:
$OOB).
The Timer/Event Counter can be initialized by writing data
into
the
Timer Load Register. In this case, write the low-order
digit first, and then the high-order digit. The Timer/Event
Counter
is
initialized at the time when the high-order digit
is
written. The Timer Load Register will
be
initialized
to
$00 by
the
MCU
reset.
The counter value
of
TIMER-B can be obtained
by
reading
PMR:$
004
the Timer/Event Counter. In this case, read the high-order digit
first, and then the low-order digit. The
count
value
of
low-order
digit
is
latched at the time when the high-order digit
is
read.
• TIMER-A Interrupt Request
Flag
(lFTA:
$001,2)
The TIMER-A Interrupt Request Flag
is
set by the overflow
output
of
TIMER-A.
• TIME R-A Interrupt Mask
(lMT
A:
$001,3)
TIMER-A Interrupt Mask prevents an interrupt request
generated by TIMER-A Interrupt Request Flag.
Table 13.
TIMER-A
Interrupt
Request Flag
TIMER-A
Interrupt
Request Flag
o
I
nterrupt
Request
No
Yes
Table 14.
TIMER-A
Interrupt
Mask
TIMER-A
Interrupt
Mask
o
Interrupt
Request
Enable
Disable
(Mask)
• TIMER-B Interrupt Request
Flag
(lFTB: $002, 0)
The TIMER-B Interrupt Request Flag
is
set by the overflow
output
of
TIMER-B.
• TIMER-B Interrupt Mask (lMTB: $002, 1)
TIMER-B Interrupt
Mask
prevents an interrupt request
generated by TIMER-B Interrupt Request Flag.
SMR:$
005
Transfer
clock
selection
R.o/SCi<
pin
mode selection
l...-
_____
R.,/Sa
pin
mode selection
'---------
R.I/SI
pin
mode selection
L-
__________
R3l/
iNT
o
pin
mode selection
l...-
____________
R33
/1NT
I
pin
mode
selection
TMA:$
008
TMB:$
009
[)<]TMA2ITMA
+MAOI
. .
teL
TI~ER-BmP"'d"'
..
,''';O"
r l
Auto-reload
function
selection
~
TIMER-A
mput
clock
selection
Fig. 14 Mode Register Configuration and Function
355
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