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17. D/A CONVERTER
17.1 PWM PINS
The PD17062 has 4 output pins for 6-bit PWM, which enables varying the duty cycle of the 15.625 kHz pulse
signal in 64 steps. With this capability, attaching an external lowpass filter to the PD17062 makes it function
as a D/A converter. The PWM pins can also be used as 1-bit output ports.
When used as a D/A converter, the PD17062 sets the D/A outputs in the output data latches, PWMRs. These
latches, PWMR0, PWMR1, PWMR2, and PWMR3, are mapped at addresses 05H, 06H, 07H, and 08H, respec-
tively. They can be read- and write-accessed via the DBF. Table 17-1 lists the correspondence between the
PWMR addresses and the PWM pins.
Table 17-1 PWMR Addresses and the Corresponding Pins
Peripheral equipment
Each PWMR consists of 7 bits. Fig. 17-1 shows the configuration of the PWMR and its correspondence with
the DBF. The highest bit of the PWMR specifies whether the PWM pin is to be used as a PWM output pin or
an output port. The other six bits specify the output values of the PWM signal.
Fig. 17-2 shows the waveform output from the PWMR pin.
Peripheral address
PWM0
05H
PWM1
06H
PWM2
07H
PWM3
08H
Corresponding pin
PWM
0
PWM
1
PWM
2
PWM
3
PD17062
217
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