AN887 Datasheet, PDF (7/12 Pages) STMicroelectronics – MICROCONTROLLERS MADE EASY

MICROCONTROLLERS MADE EASY
Output Compare. Output Compare can time an external event by sending a value stored in-
side the output compare register.
Figure 11. Input Capture and Output Capture Timer Functions
INCOMING
EVENT
value
INPUT CAPTURE
TIMER
IC register
CLOCK
OUTGOING
EVENT
OUTPUT COMPARE
value
TIMER
OC register
CLOCK
VR02101J
2.2 DIGITAL SIGNAL PROCESSORS (DSP)
Microcontrollers react to and control events, whereas DSPs execute repetitive math-intensive
algorithms. Today many embedded applications require both types of processors, and semi-
conductor manufacturers have responded by introducing microcontrollers with on-chip DSP
capability and DSPs with on-chip microcontrollers.
The most basic thing a DSP will do is a MACC (Multiply and ACCumulate). The number of
data bits a DSP can Multiply and ACCumulate will determine the dynamic range (and there-
fore the application).
2.3 ANALOG AND DIGITAL SIGNALS
We live in an analog world where the information we see, hear, process, and exchange with
each other, and with our mechanical and electronic systems, is always an analog quantity:
pressure, temperature, voltage and current are always analog entities. They can be digitized
for more efficient storage and transmission, but the interface (input and output) is almost al-
ways analog. Thus the essence of analog electronics lies in sensing continuously varying in-
formation, converting it to digital and reshaping the digital data to an analog signal at the other
end. Mixed analog-digital devices are being used increasingly to integrate the complex func-
tions of high-speed telecommunications, or the real-time data processing demanded by indus-
trial control systems and automotive systems.
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