AN2528 Freescale Semiconductor / Motorola, AN2528 Datasheet - Page 17

• Manufacturer Part Number: AN2528
• Description: Standard Space Vector Modulation TPU Function Set
• Manufacturer: Freescale Semiconductor / Motorola

Synchronized Change
of PWM Prescaler
And Synchronization
Signal Prescaler
Host Interface
MOTOROLA
Standard Space Vector Modulation TPU Function Set (svmStd)
The svmStd_sync TPU function actually uses the presc_copy parameter
instead of the prescaler parameter. The prescaler parameter holds the
prescaler value that is copied to the presc_copy by the svmStd_bottom function
at the time the PWM parameters are reloaded. This ensures that new prescaler
values for the PWM signals, as well as the synchronization signal, are applied
at the same time. Write the synchronization signal prescaler parameter
address to the sync_presc_addr parameter to enable this mechanism. Write 0
to disable it, and remember to set the synchronization signal presc_copy
parameter instead of the prescaler parameter in this case.
move > 0
move > 0
prescaler = 1
prescaler = 1
move < 0
move < 0
prescaler = 2
prescaler = 2
3
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2
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Written By CPU
Written By TPU
1
1
Figure 9. Synchronization signal adjustment examples
center_time
center_time
center_time
center_time
0
0
T
T
T
T
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pw
pw
Channel Function Select
Channel Priority
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Name
pw
pw
Table 11. svmStd_sync Control Bits
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center_time
center_time
center_time
center_time
center_time
T
T
T
T
T
T
svmStd_sync function number
00 – Channel Disabled
01 – Low Priority
10 – Middle Priority
11 – High Priority
(Assigned during assembly the
DPTRAM code from library TPU
functions)
Written by both CPU and TPU
Not Used
Detailed Function Description
Options
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center_time
T
T
AN2528/D
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