Olimex Development prototype board for 28 pin PIC microcontrollers PIC-P28-20MHz PIC-P28-20MHz 用户手册
产品代码
PIC-P28-20MHz
INTRODUCTION:
PIC-P28 board is development board which allow you to prototype and
develop code for all Microchip’s PIC microcontrollers with 28 pins.
What you can do with PIC-P28? A lot of stuff let’s see what we have:
PIC-P28 have RS232 connector and driver, so you can interface your
PIC microcontroller to other embedded or PC with RS232. The RS232
driver have 4 lines Tx, Rx, CTS and jumper selectable RTS or DTR.
The pin labeled RX is output and should be connected to PIC UART Tx.
The pin labeled TX is input and should be connected to PIC UART Rx.
Note that MAX232 driver on the socket is 5V device, so if you decide
to run your PIC on 3.3V you should replace it with MAX3232 which
works on 3.3V
The on-board ICSP connector allow you to program the PIC on the
board without pulling it of the socket, by ICSP programmer like PIC-
MCP, PIC-MCP-USB, PIC-PG1, PIC-PG2, PIC-PG3, PIC-PG4 or to
program and debug it with PIC-ICD2, PIC-ICD2-POCKET or PIC-ICD2-
TINY.
IMPORTANT: all programmers provide power supply through
ICSP connector during the programming PIC-P18 should not be
powered via the external power jack!
The power supply circuit have diode bridge after the power supply jack
which allow you to power this board with both AC and DC power
supply adapters. The input voltage could be anything within the range
+7.5 – 15V DC or 6-12V AC.
Voltage regulator is made with LM317 adjustable voltage regulator and
have jumper which selects what voltage you supply to the PIC
microcontroller +3.3V or +5V, so you can work with PICs on both low
and normal voltage.
The oscillator circuit is made with 20 Mhz crystal oscillator, so you
can run your PIC at maximum performance.
The RESET circuit is made with simple RC circuit and RESET push
button, the reason to not use RESET IC is that the board should
support both 3.3V and 5V operation while RESET ICs are on fixed
voltage.
PIC-P28 have user button for user input connected to PIC
microcontroller’s RA5 port. When RA5 port is initialized as INPUT you
will read “0” when the button is pressed and “1” when it is depressed.
Status LED is connected via jumper to PIC microcontroller’s RA0 port.
When your RA0 port is initialized as OUTPUT and set to “0” LED will
go ON, when RA0 port is set to “1” LED will go OFF.
PIC-P28 have handy GND pin for connection to oscilloscope.
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