Microchip Technology dsPICDEM 1.1 Plus, Руководство пользователя

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dsPICDEM™ 1.1 Plus Development Board User’s Guide
DS70099D-page 34
©
2006 Microchip Technology Inc.
Figure 3-9 shows the frequency response of the FIR filter implemented on the
dsPIC30F. The FIR filter is only employed for demonstrating filter operation.
FIGURE 3-9: FREQUENCY RESPONSE: FIR FILTER
The signal frequency determined by analyzing the 256-point FFT and associated bin is
displayed on the LCD. Cycle counts for the digital filters and FFT are displayed on the
LCD.
To quit this demonstration and return to the main menu, press switch SW1.
3.3.1.3 DTMF GENERATION MODE
From the Menu Options display, pressing switch SW4 launches the DTMF Generation
demo and takes you to the DTMF operation menu (Figure 3-10).
FIGURE 3-10: DTMF TONE GENERATION MENU
When this display is active, switches SW2-SW4 control tone generation, as shown in
Table 3-2.
TABLE 3-2: DTMF TONE GENERATION CONTROLS
Switch Function
SW2 Moves blinking cursor to the next DTMF Tone digit
SW3 Plays the DTMF tone associated with the digit selected by s2
SW4 Plays a predetermined sequence of ten DTMF tones
D
TMF
T
ONE
0123456789
NEXT
–s2
SELECT
–s3
PLAY SEQ
–s4
MAIN
–s1