68.7.44 PWM Channel Period Register

This register can only be written if bits WPSWS3 and WPHWS3 are cleared in the PWM Write Protection Status Register.

Only the first 16 bits (channel counter size) are significant.

Name:	PWM_CPRDx
Offset:	0x020C + x*0x20 [x=0..3]
Reset:	0x00000000
Property:	Read/Write


Bit	31	30	29	28	27	26	25	24

Access
Reset


Bit	23	22	21	20	19	18	17	16
	CPRD[23:16]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0


Bit	15	14	13	12	11	10	9	8
	CPRD[15:8]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0


Bit	7	6	5	4	3	2	1	0
	CPRD[7:0]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0

Bits 23:0 – CPRD[23:0] Channel Period

If the waveform is left-aligned, then the output waveform period depends on the channel counter source clock and can be calculated:

– By using the PWM peripheral clock divided by a given prescaler value “X” (where X = 2^PREA is 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024). The resulting period formula is:    $\frac{(X \times CPRD)}{f_{peripheral clock}}$  

– By using the PWM peripheral clock divided by a given prescaler value “X” (see above) and by either the DIVA or the DIVB divider. The formula becomes, respectively:    $\frac{(X \times CPRD \times DIVA)}{f_{peripheral clock}}$ or $\frac{(X \times CPRD \times DIVB)}{f_{peripheral clock}}$  

If the waveform is center-aligned, then the output waveform period depends on the channel counter source clock and can be calculated:

– By using the PWM peripheral clock divided by a given prescaler value “X” (where X = 2^PREA is 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, or 1024). The resulting period formula is:   $\frac{(2 \times X \times CPRD)}{f_{peripheral clock}}$  

– By using the PWM peripheral clock divided by a given prescaler value “X” (see above) and by either the DIVA or the DIVB divider. The formula becomes, respectively:   $\frac{(2 \times X \times CPRD \times DIVA)}{f_{peripheral clock}}$ or $\frac{(2 \times X \times CPRD \times DIVB)}{f_{peripheral clock}}$