DM300024 Microchip Technology, DM300024 Datasheet - Page 36

• Manufacturer Part Number: DM300024
• Description: KIT DEMO DSPICDEM 1.1
• Manufacturer: Microchip Technology
• Type: MCUr

Specifications of DM300024

• Contents: Board, Cable, CD, Power Supply
• Silicon Manufacturer: Microchip
• Core Architecture: DsPIC
• Core Sub-architecture: DsPIC30F
• Features: Serial Communication Channels Interface, General Purpose Prototyping Area
• Silicon Core Number: DsPIC30F, DsPIC33F
• Silicon Family Name: DsPIC30F6xxx, DsPIC33FJxxGPxxx
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: dsPIC30F/33F and PIC24H
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

dsPICDEM™ 1.1 Plus Development Board User’s Guide
DS70099D-page 32
3.3.1.2
From the Menu Options display, pressing switch SW3 launches the DSP Operations
demo, which displays the digital signal values shown in Figure 3-6. This display
provides information on the various signal processing operations that are performed on
the signal at analog input pin, AN3.
FIGURE 3-6:
The DSP operations display shows several parameters for a sampled sine-wave
signal. A fundamental sine-wave signal is generated by stepping the MCP41010 digital
potentiometer (U8) output at an 8 kHz rate. The output of the digital potentiometer is
applied to a Low-Pass (LP) filter with a cutoff frequency of approximately 4 kHz. This
LP filter removes the high-frequency components and yields a sine wave adequate for
this demonstration. Five frequencies are developed and selected by varying
potentiometer RP1, as shown in Table 3-1.
TABLE 3-1:
The filtered output of the MCP41010 is routed to pin AN3/RB3, which is an input to the
12-bit ADC. The ADC collects 256 samples from the MCP41010 at an 8 kHz sample
rate. These samples are optionally subjected to a digital filtering algorithm. The
following three digital filtering options are provided and selected by switch SW2:
• None
• Infinite Impulse Response (IIR)
• Finite Impulse Response (FIR)
Subsequently, their spectral components are estimated. The frequency estimate of the
signal on pin AN3/RB3 is displayed on the first row of the DSP Operations display.
DSP OPERATIONS MODE
Potentiometer Setting
0 ≤ RP1 ≤ 1V
1 ≤ RP1 ≤ 2V
2 ≤ RP1 ≤ 3V
3 ≤ RP1 ≤ 4V
4 ≤ RP1 ≤ 5V
FREQUENCIES VS. POTENTIOMETER SETTING
DSP OPERATIONS DISPLAY
F = 1000
256
I I R
MAIN
PT
– s1
T
T
FILT
FFT
CHNGFILT
=018175
=028649
B
IN
= 032
–
Resulting Frequency
CY
CY
S
2
© 2006 Microchip Technology Inc.
1000 Hz
1500 Hz
2000 Hz
100 Hz
500 Hz