TMP92CF30
2009-06-12
92CF30-261
In this mode the value of the register buffer will be shifted into TA0REG if 2
n
overflow is detected when the TA0REG double buffer is enabled.
Use of the double buffer facilitates the handling of low duty ratio waves.
Figure 3.12.24 Register Buffer Operation
Example: To output the following PWM waves on the TA1OUT pin (at f
SYS
=
50 MHz).
To achieve a 20.48
μ
s PWM cycle by setting
φ
T1 to 0.16
μ
s (at f
SYS
=
50 MHz):
20.48
μ
s
÷
0.16
μ
s
=
128
2
n
=
128
Therefore n should be set to 7.
Since the low level period is 16.0
μ
s when
φ
T1
=
0.16
μ
s,
set the following value for TAREG:
16.0
μ
s
÷
0.16
μ
s
=
100
=
64H
* Clock state
Clcok gear :
1/1
Prescaler of clock gear : 1/2
MSB
LSB
7
6
5
4
3
2
1
0
TA01RUN
← −
X X X
−
−
−
0
Stop TMRA0 and clear it to 0
TA01MOD
←
1
1
1
0
X
X
0
1
Select 8-bit PWM mode (cycle: 2
7
) and select
φ
T1 as the
input clock.
TA0REG
←
0
1
1
0
0
1
0
0
Write 64H.
TA1FFCR
←
X
X
X
X
1
0
1
X
Clear TA1FF to 0, enable the inversion and double buffer.
PM
← −
X X X X
−
0
X
PMFC
← −
X X X X
−
1
X
Set PM1 as the TA1OUT pin.
TA01RUN
←
1 X X X
−
1
−
1
Start TMRA0 counting.
X: Don't care,
−
: No change
16.0
μ
s
20.48
μ
s
Q
2
Q
1
Match with TA0REG
Q
3
Q
2
Up counter
=
Q
1
Up
counter
=
Q
2
Shift into TA0REG(Register buffer0)
TA0REG (Register buffer0)
write
TA0REG
(Value to be compared)
Register buffer0
2
n
overflow
Summary of Contents for TLCS-900/H1 Series
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