PIC-P28 development board Users Manual All boards produced by Olimex are ROHS compliant Rev. D, February 2008 Copyright(c) 2008, OLIMEX Ltd, All rights reserved Page 1INTRODUCTION: PIC-P28 board is development board which allow you to prototype and develop code for all Microchips PIC microcontrollers with 28 pins. What you can do with PIC-P28 A lot of stuff lets 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 microcontrollers 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 microcontrollers 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. Page 2