16-07-2012, 12:47 PM
MICROCONTROLLER INTERFACING CIRCUITS
MICROCONTROLLER INTERFACING CIRCUITS.pdf (Size: 286.29 KB / Downloads: 28)
What is a PIC Microcontroller?
A PIC microcontroller is a single integrated circuit small enough to fit in the palm of a
hand. ‘Traditional’ microprocessor circuits contain four or five separate integrated
circuits - the microprocessor (CPU) itself, an EPROM program memory chip, some
RAM memory and an input/output interface. With PIC microcontrollers all these
functions are included within one single package, making them cost effective and easy
to use.
PIC microcontrollers can be used as the ‘brain’ to control a large variety of products. In
order to control devices, it is necessary to interface (or ‘connect’) them to the PIC
microcontroller. This section will help to enable those with limited electronics
experience to successfully complete these interfacing tasks.
What is a PICAXE microcontroller?
A PICAXE microcontroller is a standard Microchip PICmicro™ microcontroller that has
been pre-programmed with the PICAXE bootstrap code. The bootstrap code enables
the PICAXE microcontroller to be re-programmed directly via a simple serial
connection. This eliminates the need for an (expensive) conventional programmer,
making the whole download system a very low-cost simple serial cable!
The pre-programmed bootstrap code also contains common routines (such as how to
generate a pause delay or a sound output), so that each download does not have to
waste time downloading this commonly required data. This makes the download time
much quicker.
Interfacing to the PICAXE Microcontroller
This section explains how to interface many different input and output devices to the
PICAXE microcontroller. Explanations of BASIC commands are provided in the
Commands section (available separately). The interfacing circuits can also be used
with any other PIC microcontrollers such as the PIC16F84A, although these
microcontrollers may require programming in assembler code.
This section is split into four subsections:
• Introduction to ‘standard’ interfacing circuits
• Output Device Interfacing
• Input Device Interfacing
• Advanced Component Interfacing