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Document # 001-20559 Rev. *D
Digital Blocks
17.3.3
Dead Band Timing
Enable/Disable Operation.
Initially both outputs are low.
There are no critical timing requirements for enabling the
block because dead band processing does not start until the
first incoming positive or negative reference edge. In typical
operation, it is recommended that the dead band block be
enabled first, then the Pulse Width Modulator (PWM) gener-
ator block.
When the block is disabled, the clock is immediately gated
low. All outputs are gated low, including the interrupt output.
All internal states are reset to their configuration-specific
reset state, except for DR0, DR1, and DR2 which are unaf-
fected.
shows typical dead band
timing. The incoming reference edge can occur up to one 24
MHz system clock before the edge of the block clock. On
the edge of the block clock, the currently asserted output is
negated and the dead band counter is enabled. After Period
+ 1 clocks, the phase associated with the current state of the
PWM reference is asserted (Reference High = Phase 1,
Reference Low = Phase 2). The minimum dead time occurs
with a period value of 00h and that dead time is one clock
cycle.
Figure 17-9. Basic Dead Band Timing
17.3.3.1
Changing the PWM Duty Cycle
Under normal circumstances, the dead band period is less
than the minimum PWM high or low time. As an example,
consider
where the low of the PWM is four
clocks, the dead band period is two clocks, and the high
time of the PHI2 is two clocks.
Figure 17-10. DB High Time is PWM Width Minus DB
Period
illustrates the reduction of the width of the
PWM low time by one clock (to three clocks). The dead
band period remains the same, but the high time for PHI2 is
reduced by one clock (to one clock). Of course the opposite
phase, PHI1, increases in length by one clock.
Figure 17-11. DB High Time is Reduced as PWM Width is
Reduced
CLOCK
PWM REFERENCE
PHI2 (Auxiliary Output)
Dead Time
PHI1 (Primary Output)
Dead time in clocks is
the Period + 1.
A PWM reference edge
running on the same
clock occurs here.
A Bit-Bang clock can occur
anywhere up to one 24
MHz clock, before the next
block clock edge.
A high on the reference
asserts PH1, a low PHI2.
COUNT
P-1
P-2
1
0
P
P
CLK
PWM
PHI1
PHI2
2
2
2
4
CLK
PWM
PHI1
PHI2
2
2
1
3
Содержание PSoC CY8C23533
Страница 4: ...Contents Overview 4 Document 001 20559 Rev D Section G Glossary 385 Index 401 ...
Страница 16: ...Contents Overview 16 Document 001 20559 Rev D ...
Страница 24: ...24 Document 001 20559 Rev D Section A Overview ...
Страница 30: ...30 Document 001 20559 Rev D Pin Information ...
Страница 54: ...54 Document 001 20559 Rev D Supervisory ROM SROM ...
Страница 60: ...60 Document 001 20559 Rev D RAM Paging ...
Страница 68: ...68 Document 001 20559 Rev D Interrupt Controller ...
Страница 76: ...12 Document 001 20559 Rev D General Purpose IO GPIO ...
Страница 82: ...18 Document 001 20559 Rev D Internal Main Oscillator IMO ...
Страница 84: ...20 Document 001 20559 Rev D Internal Low Speed Oscillator ILO ...
Страница 90: ...26 Document 001 20559 Rev D External Crystal Oscillator ECO ...
Страница 94: ...30 Document 001 20559 Rev D Phase Locked Loop PLL ...
Страница 106: ...42 Document 001 20559 Rev D Sleep and Watchdog ...
Страница 228: ...164 Document 001 20559 Rev D Section D Digital System ...
Страница 234: ...170 Document 001 20559 Rev D Array Digital Interconnect ADI ...
Страница 278: ...214 Document 001 20559 Rev D Digital Blocks ...
Страница 296: ...232 Document 001 20559 Rev D Analog Interface ...
Страница 304: ...240 Document 001 20559 Rev D Analog Array ...
Страница 308: ...244 Document 001 20559 Rev D Analog Input Configuration ...
Страница 312: ...248 Document 001 20559 Rev D Analog Reference ...
Страница 338: ...274 Document 001 20559 Rev D Section F System Resources ...
Страница 354: ...290 Document 001 20559 Rev D Multiply Accumulate MAC ...
Страница 374: ...310 Document 001 20559 Rev D I2C ...
Страница 400: ...336 Document 001 20559 Rev D Section G Glossary ...