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Section 9 14-Bit PWM Timer (PWMX)
9.3.2
PWMX (D/A) Data Registers A and B (DADRA and DADRB)
DADRA corresponds to PWMX (D/A) channel A, and DADRB to PWMX (D/A) channel B. The
DADR registers cannot be accessed in 8-bit units. The DADR registers should always be accessed
in 16-bit units. For details, see section 9.4, Bus Master Interface.
• DADRA
Bit
Bit Name
15 to 2 DA13 to DA0 All 1
1
CFS
0
Rev. 1.00 Mar. 12, 2008 Page 360 of 1178
REJ09B0403-0100
Initial
Value
R/W
Description
R/W
D/A Data 13 to 0
These bits set a digital value to be converted to an
analog value.
In each base cycle, the DACNT value is continually
compared with the DADR value to determine the duty
cycle of the output waveform, and to decide whether to
output a fine-adjustment pulse equal in width to the
resolution. To enable this operation, this register must be
set within a range that depends on the CFS bit. If the
DADR value is outside this range, the PWM output is
held constant.
A channel can be operated with 12-bit precision by fixing
DA0 and DA1 to 0. The two data bits are not compared
with UC12 and UC13 of DACNT.
1
R/W
Carrier Frequency Select
0: Base cycle = resolution (T) × 64
The range of DA13 to DA0: H'0100 to H'3FFF
1: Base cycle = resolution (T) × 256
The range of DA13 to DA0: H'0040 to H'3FFF
1
R
Reserved
This bit is always read as 1 and cannot be modified.
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