资料介绍
The PIC16C74 is one of the latest mid-range microcon-trollers from Microchip Technology Inc. In this article we
will be addressing a few of the new features and
peripherals of this new part. The main focus will be on
the A/D (Analog-to-Digital) Converter, the SCI (Serial
Communication Interface), and the PWM (Pulse Width
Modulator). Our intention is to give you a small program
that initializes these peripherals as well as exercises
them. A schematic is provided. The PICDEM
TM
2 board
from Microchip will run this program. The second trim-pot does not exist on the PICDEM 2 board, so the sec-ond A/D value may float around. The second trimpot is
only used to show a method of changing A/D input pins.
If you are using the PICDEM 2 board, then the LED and
a current limiting resistor must be connected to the
PWM output. When the program is run, the RS-232 ter-minal will display two A/D values. The brightness of an
LED is adjusted using pulse width modulation. The duty
cycle is determined by the trimpot setting.
M FACT003
Care and Feeding of the PIC16C74 and Its Peripherals
A/D Converter Mysteries
Author: Robert Angelo
The A/D converter and its eight input channels will be
Microchip Technology Inc.
our first topic. Setting up the A/D converter involves two
special function registers:
ADCON0
The PIC16C74 is one of the latest mid-range microcon-
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