Digital Control
Digital Control
Digital Control
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►Need to calculate the<br />
next edge position for<br />
rising and falling edges<br />
within very short period.<br />
►Software not fast<br />
enough so need<br />
hardware adder<br />
►Diagram shows 21 bit<br />
adder to control both<br />
edges automatically<br />
setting new comparator<br />
values after each edge<br />
has been triggered<br />
Ideal timing<br />
16 bits<br />
at IP Bus<br />
timing<br />
resolution<br />
5 bits<br />
NanoEdge<br />
timing<br />
resolution<br />
<strong>Digital</strong> Adder for Frequency <strong>Control</strong><br />
16 bit + 5 bit<br />
adder<br />
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Reg. U.S. Pat. & Tm. Off. BeeKit, BeeStack, CoreNet, the Energy Efficient Solutions logo, Flexis, MXC, Platform in a Package, Processor Expert, QorIQ, QUICC Engine, SMARTMOS, TurboLink<br />
and VortiQa are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © 2010 Freescale Semiconductor, Inc. 59<br />
Actual timing Timer<br />
16 bits<br />
at IP Bus<br />
timing<br />
resolution<br />
5 bits<br />
NanoEdge<br />
timing<br />
resolution<br />
16 bits<br />
at IP Bus<br />
timing<br />
resolution<br />
5 bits<br />
NanoEdge<br />
timing<br />
resolution<br />
resolution resolution resolution<br />
PWM<br />
Period N<br />
PWM Period N-1<br />
5 bits from previous Nano Edge<br />
Placement calculation<br />
PWM<br />
Period N<br />
PWM reload times are restricted to 16-bit IP Bus timing<br />
(truncation of 21 bit value). Any residual left over from<br />
PWM period N-1 needs to be added back to period N.<br />
TM
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