gc80c520a CORERIVER Semiconductor, gc80c520a Datasheet - Page 57

• Manufacturer Part Number: gc80c520a
• Description: Midas1.0 Family Mask Rom/eprom/romless 8-bit Turbo Microcontrollers
• Manufacturer: CORERIVER Semiconductor

6.2.6.3 PWM counter
A PWM counter operates in the two modes. One is the 8-bit counter mode. In this mode, the PWM
counter operates as an 8-bit counter. A period of PWM output starts at the overflow of the counter. The
duty rate of the PWM output is determined by comparing the value of the 8-bit counter with that of
PWM0D or PWM1D. The mode is used for low frequency applications. The other is the 6-bit counter and
2-bit extension mode. In this mode, the period of the PWM output starts at the overflow of the lower 6-bits
of the counter. The duty rate of the PWM output is determined by comparing the value of the lower 6-bits
with that of PWM0D[5:0] or PWM1D[5:0]. In order to enhance resolutions, the pulse width of the PWM
output can lengthen by one clock cycle according to the rule between the 2-bit extension and
PWM0D[7:6]/PWM1D[7:6]. The mode is used for high frequency applications.
6.2.6.4 PWM frequency
The period of the PWM output are based on the prescaled PWM clock frequency. The PWM counter
clock frequency is determined by the value of PWM0CON[6:4] or PWM1CON[6:4]. Table 6-9 shows the
clock prescaling rate determined by the value of PWM0CON[6:4] or PWM1CON[6:4].
A PWM output pin (P3.4/PWM0 or P1.0/PWM1)
MiDAS1.0 Family
Table 6-9 PWM clock scaling rate determined by PWM0CON[6:4]/PWM1CON[6:4]
PWM0CON[6:4]/PWM1CON[6:4]
000
001
010
011
100
101
110
111
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PWM clock prescaling rate
F
F
F
F
OSC
F
F
F
F
OSC
OSC
OSC
OSC
OSC
OSC
OSC
/128
/16
/32
/64
/1
/2
/4
/8