PIC CHIP PROGRAMS.
1/ PHILIPS PRN4004 VOTING SYSTEM. VOTED SITE DECODER. This enables the voted site to be displayed on a Seven Segment LED Display.Normally a dumb terminal or PC would be used to monitor the serial port, but for convenience this unit was built in a small plastic RS type box and powered from a battery. The principle is that the 4800, 8, N ,1 serial data is fed direct to an input line of PortA, this is decoded and the program has a routine that looks for the sequence of ASCII characters that precede the site number digit. Having passed this test the digit is then displayed.The seven segment display is driven directly from the PortB lines. The conversion from decimal to seven segment is done by means of a look up table. Download PRN4004 Decoder
2/ PHILIPS PRN3020 VOTING SYSTEM VOTED SITE DECODER This is a similar program to the above, but is designed for the older type of voter. Download PRN3020 Decoder
3/ CALL SIGN GENERATOR. This is a Morse call sign generator, the code is read from a look up table where each Morse character is represented by using ones for a dot tone period. The dashes are made up by three ones and the spaces by zero's. To make up spaces between dots and dashes three zero's are used and five between each word. The PortA lines RA0, and RA1 are connected to a centre off switch, such that if RA0 is high then the Morse string is generated, if RA1 is high the program will generate a continuous tone for transmitter tune up. The output which is squarewave, is taken from any of the PortB lines. Download Callsign Generator
4/ TIMER.This is a general purpose timer capable of accurately timing periods up to 255 minutes. The main element is built round an interrupt routine which counts milliseconds to make a one second period and then counts the second to make a one minute period. The program is set up to count three minutes and light an LED, then light another LED after four minutes, then after five minutes it changes the condition on PortB line 5. The program was written to demonstrate the feasibility of making a timer to switch off a battery charger after a couple of hours, and have the facility to be reset and repeat the operation. Download Timer