Figure 7.1 Example D/A Converter Configuration Using Pwm Output And Low Pass Filter - Fujitsu F2MC-8L MB89620 Series Hardware Manual

n PWM Timer Function
The PWM timer function has 8-bit resolution and can control the "H" and "L" widths of one cycle.
• As the resolution is 1/256, pulses can be output with duty ratios of between 0 and 99.6%.
• The cycle of the PWM wave can be selected from four types.
• The PWM timer can be used as a D/A converter by connecting the output to a low pass filter.
Table 7.1b lists the available PWM wave cycles for the PWM timer function. Figure 7.1 shows
an example D/A converter configuration.
Table 7.1b Available PWM Wave Cycle for PWM Timer Function
Count clock cycle
PWM wave cycle
t : Instruction cycle (divide-by-four source oscillation)
inst
PWC output cycle: Timer output bit of the pulse width count timer (PCR2: TO)

Figure 7.1 Example D/A Converter Configuration Using PWM Output and Low Pass Filter

Note: Interrupt requests are not generated during operation of the PWM function.
MB89620 series
1 2 3
Internal count clock
1 t 16 t 64 t
inst inst inst
12
2 8 t 2 t 2 14 t 2
inst
inst inst
4
PWC output cycle
2 t to 2 9 t 2 3 t to 2 11
inst inst inst
9 t to 2 17 t 2 11 t to 2 19
inst inst inst
CHAPTER 7 8-BIT PWM TIMER
6 14
t 2 t to 2 t
inst inst
inst
14 22
t 2 t to 2 t
inst inst
inst
139