975
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
37.7.40
PWM Channel Period Update Register
Name:
PWM_CPRDUPDx [x=0..3]
Address:
0x40020210 [0], 0x40020230 [1], 0x40020250 [2], 0x40020270 [3]
Access:
Write-only
This register can only be written if the bits WPSWS3 and WPHWS3 are cleared in
“PWM Write Protect Status Register” on
This register acts as a double buffer for the CPRD value. This prevents an unexpected waveform when modifying the
waveform period.
Only the first 16 bits (channel counter size) are significant.
• CPRDUPD: Channel Period Update
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 master clock (MCK) divided by an X given prescaler value (with X being 1, 2, 4, 8, 16, 32,
64, 128, 256, 512, or 1024). The resulting period formula will be:
– By using the PWM master clock (MCK) divided by one of both DIVA or DIVB divider, the formula becomes,
respectively:
or
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 master clock (MCK) divided by an X given prescaler value (with X being 1, 2, 4, 8, 16, 32,
64, 128, 256, 512, or 1024). The resulting period formula will be:
– By using the PWM master clock (MCK) divided by one of both DIVA or DIVB divider, the formula becomes,
respectively:
or
31
30
29
28
27
26
25
24
–
–
–
–
–
–
–
–
23
22
21
20
19
18
17
16
CPRDUPD
15
14
13
12
11
10
9
8
CPRDUPD
7
6
5
4
3
2
1
0
CPRDUPD
X
CPRDUPD
×
(
)
MCK
---------------------------------------------
CRPDUPD
DIVA
×
(
)
MCK
---------------------------------------------------------
CRPDUPD
DIVB
×
(
)
MCK
---------------------------------------------------------
2
X
CPRDUPD
×
×
(
)
MCK
--------------------------------------------------------
2
CPRDUPD
DIVA
×
×
(
)
MCK
-------------------------------------------------------------------
2
CPRDUPD
×
DIVB
×
(
)
MCK
-------------------------------------------------------------------
Summary of Contents for SAM4S Series
Page 44: ...44 11100B ATARM 31 Jul 12 SAM4S Series Preliminary ...
Page 412: ...412 11100B ATARM 31 Jul 12 SAM4S Series Preliminary ...
Page 1105: ...1105 11100B ATARM 31 Jul 12 SAM4S Series Preliminary ...
Page 1143: ...1143 11100B ATARM 31 Jul 12 SAM4S Series Preliminary Figure 43 4 64 lead LQFP Package Drawing ...
Page 1145: ...1145 11100B ATARM 31 Jul 12 SAM4S Series Preliminary Figure 43 5 64 lead QFN Package Drawing ...