NEC PD17062 - Manual (Page 217)

217
µ
PD17062
Peripheral equipment Peripheral address Corresponding pin
PWM0 05H PWM 0
PWM1 06H PWM
1
PWM2 07H PWM
2
PWM3 08H PWM 3
17. D/A CONVERTER
17.1 PWM PINS
The
µ
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
µ
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
µ
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
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.