DV164101 Microchip Technology, DV164101 Datasheet - Page 62

• Manufacturer Part Number: DV164101
• Description: KIT DEV PICKIT1 FLASH 8/14PIN
• Manufacturer: Microchip Technology
• Series: PICkit™ 1r
• Type: MCUr

Specifications of DV164101

• Contents: PIC Kit 1 Circuit Board, CD-ROMs, USB Interface Cable and Booklet
• Processor To Be Evaluated: PIC12F675
• Interface Type: USB
• Silicon Manufacturer: Microchip
• Core Architecture: PIC
• Core Sub-architecture: PIC12, PIC16
• Silicon Core Number: PIC12F, PIC16F
• Silicon Family Name: PIC12F6xx, PIC16F6xx
• Rohs Compliant: NA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: Microchip's 8-14 Pin FLASH Microcontrollers
• For Use With: AC164122 - BOARD DAUGHT PICTAIL SD/MMC CARDAC164120 - BOARD SIGNAL ANALYSIS PICKIT
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: DV164101R; DV164101R

PICkit
DS40051D-page 58
™
1 Flash Starter Kit User’s Guide
C.6.2
This lesson uses the PIC12F675 and demonstrates an interrupt based analog-to-
digital conversion. TMR0 is set up with a prescaler of 4, thus creating an interrupt
roughly every 1 ms. With every TMR0 interrupt, either the LED display routine is
serviced (see Lesson 3) or the A/D routine is serviced depending on the flag that tog-
gles with every interrupt. Noise is generated on V
Therefore, to reduce noise in the A/D process, either a new A/D conversion is done or
the display is updated, but not simultaneously. The A/D interrupt source is not used
because the service interval (2 ms) is much longer than the conversion period of 22 s.
The A/D module requires at least 4 s for the sample capacitor to charge between
acquisitions, but the program allows for about 2 ms. The result of the A/D is 10 bits,
even though only the eight most significant bits are displayed on the LEDs. The result
is left justified (ADFM = 0) and the most significant byte is written to the LEDREGISTER
to be displayed. The ANSEL register specifies which of the general purpose I/O pins
are to be configured as analog inputs to the A/D module. In this case, the potentiome-
ter's output serves as the input to AN0.
Figure C-12 shows the source code files for the assembly and C projects respectively.
FIGURE C-12:
Analog-to-Digital Converter Lesson
ASSEMBLY AND C SOURCE CODE FILES
DD
when the LEDs are updated.
 2004 Microchip Technology Inc.