200
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
Summary of Contents for PSoC CY8C23533
Page 4: ...Contents Overview 4 Document 001 20559 Rev D Section G Glossary 385 Index 401 ...
Page 16: ...Contents Overview 16 Document 001 20559 Rev D ...
Page 24: ...24 Document 001 20559 Rev D Section A Overview ...
Page 30: ...30 Document 001 20559 Rev D Pin Information ...
Page 54: ...54 Document 001 20559 Rev D Supervisory ROM SROM ...
Page 60: ...60 Document 001 20559 Rev D RAM Paging ...
Page 68: ...68 Document 001 20559 Rev D Interrupt Controller ...
Page 76: ...12 Document 001 20559 Rev D General Purpose IO GPIO ...
Page 82: ...18 Document 001 20559 Rev D Internal Main Oscillator IMO ...
Page 84: ...20 Document 001 20559 Rev D Internal Low Speed Oscillator ILO ...
Page 90: ...26 Document 001 20559 Rev D External Crystal Oscillator ECO ...
Page 94: ...30 Document 001 20559 Rev D Phase Locked Loop PLL ...
Page 106: ...42 Document 001 20559 Rev D Sleep and Watchdog ...
Page 228: ...164 Document 001 20559 Rev D Section D Digital System ...
Page 234: ...170 Document 001 20559 Rev D Array Digital Interconnect ADI ...
Page 278: ...214 Document 001 20559 Rev D Digital Blocks ...
Page 296: ...232 Document 001 20559 Rev D Analog Interface ...
Page 304: ...240 Document 001 20559 Rev D Analog Array ...
Page 308: ...244 Document 001 20559 Rev D Analog Input Configuration ...
Page 312: ...248 Document 001 20559 Rev D Analog Reference ...
Page 338: ...274 Document 001 20559 Rev D Section F System Resources ...
Page 354: ...290 Document 001 20559 Rev D Multiply Accumulate MAC ...
Page 374: ...310 Document 001 20559 Rev D I2C ...
Page 400: ...336 Document 001 20559 Rev D Section G Glossary ...