Datasheet

Introduction
M68HC12B Family Data Sheet, Rev. 9.1
Freescale Semiconductor 127
Figure 11-3. PWM Clock Sources
8-BIT DOWN COUNTER
PCLK2
MUX
PCLK3
MUX
CLOCK TO PWM
CHANNEL 2
CLOCK TO PWM
CHANNEL 3
÷ 2
PWSCNT1
8-BIT SCALE REGISTER
PWSCAL1
CLOCK B
CLOCK S1**
**CLOCK S1 = (CLOCK B)/2, (CLOCK B)/4, (CLOCK B)/6,... (CLOCK B)/512
÷ 2
0:0:0
0:0:1
0:1:0
0:1:1
1:0:0
1:0:1
1:1:0
1:1:1
÷ 2
÷ 2
÷ 2
÷ 2
÷ 2
÷ 2
0:0:0
0:0:1
0:1:0
0:1:1
1:0:0
1:0:1
1:1:0
1:1:1
8-BIT DOWN COUNTER
PCLK0
MUX
PCLK1
MUX
CLOCK TO PWM
CHANNEL 0
CLOCK TO PWM
CHANNEL 1
÷ 2
PWSCNT0
8-BIT SCALE REGISTER
PWSCAL0
CLOCK A
CLOCK S0*
*CLOCK S0 = (CLOCK A)/2, (CLOCK A)/4, (CLOCK A)/6,... (CLOCK A)/512
REGISTER: BITS:
PCKB2,
PCKB0
PCKB1,
= 0
= 0
BITS:
PCKA2,
PCKA0
PCKA1,
PWPRES
PSBCK
LIMBDM
ECLK
PSBCK IS BIT 0 OF PWCTL REGISTER.
INTERNAL SIGNAL LIMBDM IS 1 IF THE MCU IS IN BACKGROUND DEBUG MODE.