Chapter 9 Pulse-Width Modulator (S12PWM8B8CV2)
S12ZVHY/S12ZVHL Family Reference Manual Rev. 1.05
336
Freescale Semiconductor
The clock source of each PWM channel is determined by PCLKx bits in PWMCLK (see
“PWM Clock Select Register (PWMCLK)
) and PCLKABx bits in PWMCLKAB as shown in
and
9.3.2.8
PWM Scale A Register (PWMSCLA)
PWMSCLA is the programmable scale value used in scaling clock A to generate clock SA. Clock SA is
generated by taking clock A, dividing it by the value in the PWMSCLA register and dividing that by two.
Clock SA = Clock A / (2 * PWMSCLA)
NOTE
When PWMSCLA = $00, PWMSCLA value is considered a full scale value
of 256. Clock A is thus divided by 512.
Any value written to this register will cause the scale counter to load the new scale value (PWMSCLA).
Read: Anytime
Write: Anytime (causes the scale counter to load the PWMSCLA value)
9.3.2.9
PWM Scale B Register (PWMSCLB)
PWMSCLB is the programmable scale value used in scaling clock B to generate clock SB. Clock SB is
generated by taking clock B, dividing it by the value in the PWMSCLB register and dividing that by two.
Clock SB = Clock B / (2 * PWMSCLB)
NOTE
When PWMSCLB = $00, PWMSCLB value is considered a full scale value
of 256. Clock B is thus divided by 512.
Any value written to this register will cause the scale counter to load the new scale value (PWMSCLB).
Read: Anytime
Write: Anytime (causes the scale counter to load the PWMSCLB value).
Module Base + 0x0008
7
6
5
4
3
2
1
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
Reset
0
0
0
0
0
0
0
0
Figure 9-10. PWM Scale A Register (PWMSCLA)
Module Base + 0x0009
7
6
5
4
3
2
1
0
R
Bit 7
6
5
4
3
2
1
Bit 0
W
Reset
0
0
0
0
0
0
0
0
Figure 9-11. PWM Scale B Register (PWMSCLB)
