Datasheet
Section 14 14-Bit PWM D/A
(This function is not available in the H8S/2695)
R01UH0166EJ0600 Rev. 6.00 Page 691 of 1434
Mar 02, 2011
H8S/2633 Group, H8S/2633 F-ZTAT
TM
,
H8S/2633R F-ZTAT
TM
, H8S/2695
14.2.2 PWM D/A Data Registers A and B (DADRA and DADRB)
15
13
DA13
1
R/W
14
12
DA12
1
R/W
13
11
DA11
1
R/W
12
10
DA10
1
R/W
11
9
DA9
1
R/W
8
6
DA6
1
R/W
10
8
DA8
1
R/W
9
7
DA7
1
R/W
Bit (CPU)
Bit (Data)
DADRA
Initial value :
R/W :
7
5
DA5
1
R/W
6
4
DA4
1
R/W
5
3
DA3
1
R/W
4
2
DA2
1
R/W
3
1
DA1
1
R/W
0
—
—
1
—
2
0
DA0
1
R/W
1
—
CFS
1
R/W
DADRH
DADRL
DA13
1
R/W
DA12
1
R/W
DA11
1
R/W
DA10
1
R/W
DA9
1
R/W
DA6
1
R/W
DA8
1
R/W
DA7
1
R/W
DADRB
Initial value :
R/W :
DA5
1
R/W
DA4
1
R/W
DA3
1
R/W
DA2
1
R/W
DA1
1
R/W
REGS
1
R/W
DA0
1
R/W
CFS
1
R/W
There are two 16-bit readable/writable PWM D/A data registers: DADRA and DADRB. DADRA
corresponds to PWM D/A channel A, and DADRB to PWM D/A channel B. The CPU can read
and write the PWM D/A data register values, but since DADRA and DADRB are 16-bit registers,
data transfers between them and the CPU are performed using a temporary register (TEMP). See
section 14.3, Bus Master Interface, for details.
The least significant (CPU) bit of DADRA is not used and is always read as 1.
DADR is initialized to H'FFFF by a reset, and in the standby modes, watch mode, subactive mode,
subsleep mode, and module stop mode.
Bits 15 to 3—PWM D/A Data 13 to 0 (DA13 to DA0): The digital value to be converted to an
analog value is set in the upper 14 bits of the PWM D/A data register.
In each base cycle, the DACNT value is continually compared with these upper 14 bits 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, the data register must
be set within a range that depends on the carrier frequency select bit (CFS). If the DADR value is
outside this range, the PWM output is held constant.
A channel can be operated with 12-bit precision by keeping the two lowest data bits (DA0 and
DA1) cleared to 0 and writing the data to be converted in the upper 12 bits. The two lowest data
bits correspond to the two highest counter (DACNT) bits.