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From www.micro-examples.com
An On-Screen-Display with only 5 components !
PicoOClock : Turn your oscilloscope into a digital clock
Let me introduce PicoOClock to you with this short video clip :
- ==Circuit Schematic==
- ==C Source code==
- /*
- *******************************************************************************
- * PICOCLOCK : PIC Oscilloscope CLOCK
- *******************************************************************************
- *
- * This program shows how to display a digital clock on an oscilloscope
- * with a PIC and only 4 resistors.
- *
- * Circuit schematics :
- *
- * ------------+
- *
- * PIC
____
- * RB1 +----
____|-----+---------> to oscilloscope Y input
- *
680 |
- *
+-+
- *
| | 330
- *
+-+
- *
____ |
- * RB0 +----
____|-----+
- *
680 |
- * ------------+ +-+
- *
| 680
- * +-+
- *
- * -----
- * --- GND
- * -
- *
- * Oscilloscope setup :
- * set timebase to 0.1 ms, V/div = 1 V
- * select external trigger.
- *
- * source code for mikro C compiler V7.0.0.3
- * feel free to use this code at your own risks
- * and don't bother me if you get addicted watching this clock.
- *
- * target : PIC16 or PIC18, 16 Mhz crystal
- * HS clock, no watchdog.
- *
- * tested with PIC16F84A and PIC16F877A
- *
- * Author : Bruno Gavand, October 2007
- * see more details on http://www.micro-examples.com/
- *
- *******************************************************************************
- */
- /*
- * 2 bits R2R DAC gives 4 output levels :
- */
- /*
- * 10 digits 7 segment encoding + blank
- */
- /*
- * slot index for digit start
- */
- /*
- * time slot encoded line flags :
- * bit 0 is upper line
- * bit 1 is middle line
- * bit 2 is lower line
- * (if no line flag is set, spot is redirected to lowest line)
- * bit 6 is lower vertical bar
- * bit 7 is upper vertical bar
- */
- Unsigned char dIdx = 0 ; // time slot counter
- Unsigned char fIdx = 0 ; // frame counter
- Unsigned int scaler = 0 ; // RTC scaler
- Unsigned char ss = 0, mn = 0, hh = 0 ; // RTC
- /*
- * around 10 micro-second delay
- */
- Void delay10us()
- Delay us(10) ;
- /*
- * ISR
- */
- Void interrupt(void)
- If(INTCON.T0IF) // if timer 0 overflow
- Scaler++ ; // increment scaler
- Scaler = 0 ; // clear scaler
- Ss++ ; // next second
- If(ss == 60) // last second in minute ?
- Ss = 0 ; // clear second
- Mn++ ; // next minute
- If(mn == 60) // last minute in hour ?
- Mn = 0 ; // clear minute
- Hh++ ; // next hour
- If(hh == 24) // last hour in day ?
- Hh = 0 ; // clear hour
- LOW, HIGH, LOW, HIGH ;
- LOW, HIGH, LOW, HIGH ;
- LOW, HIGH, LOW, HIGH ;
- LOW, HIGH, LOW, HIGH ;
- LOW, HIGH, LOW, HIGH ;
- LOW, HIGH, LOW, HIGH ;
- LOW, HIGH, LOW, HIGH ;
- LOW, HIGH, LOW, HIGH ;
- MID, LOW, MID, LOW ;
- MID, LOW, MID, LOW ;
- MID, LOW, MID, LOW ;
- MID, LOW, MID, LOW ;
- MID, LOW, MID, LOW ;
- MID, LOW, MID, LOW ;
- MID, LOW, MID, LOW ;
- MID, LOW, MID, LOW ;
- MID, HIGH, MID, HIGH ;
- MID, HIGH, MID, HIGH ;
- MID, HIGH, MID, HIGH ;
- MID, HIGH, MID, HIGH ;
- MID, HIGH, MID, HIGH ;
- MID, HIGH, MID, HIGH ;
- MID, HIGH, MID, HIGH ;
- MID, HIGH, MID, HIGH ;
- If(dIdx == 7) // hour : minute separator
- LOW, Delay10us() ;
- MID, Delay10us() ;
- Else if(dIdx == 14) // minute : second separator
- LOW, Delay10us() ;
- MID, Delay10us() ;
- Switch(fIdx) // depending on frame index
- Case 0: // upper line
- HIGH ;
- Else
- ZERO ;
- Break ;
- Case 1: // middle line
- MID ;
- Else
- ZERO ;
- Break ;
- Case 2: // lower line
- LOW ;
- Else
- ZERO ;
- Break ;
- DIdx++ ; // next slot
- If(dIdx == SLOTS) // last slot ?
- DIdx = 0 ; // clear slot
- TRIGGER = 1 ; // triggers the scope
- FIdx++ ; // next frame
- If(fIdx == 3) // last frame ?
- FIdx = 0 ; // clear frame
- TRIGGER = 0 ; // end trigger
- INTCON.T0IF = 0 ; // clear timer 0 overflow
- /*
- * main entry
- */
- Void main()
- /*
- * set PORTA as digital I/O
- */
- ADCON1 = 7 ;
- CMCON = 7 ;
- TRISA = 0b110 ; // PORTA direction register
- PORTA = 0 ;
- TRISB = 0 ; // PORTB is output
- PORTB = 0 ;
- /*
- * clear buffers
- */
- Memset(&line, 0, sizeof(line)) ;
- Memset(display, 0, sizeof(display)) ;
- OPTION REG = 0b11011000 ; // timer 0 prescaler is 1:1
- INTCON = 0b10100000 ; // start interrupts
- For(;;) // main loop
- Unsigned char i ;
- If(KEY) // is a button pressed ?
- If(KEY MIN UP) // adjust minutes
- Ss = 0 ;
- Mn++ ;
- Else if(KEY HH UP) // adjust hours
- Ss = 0 ;
- Hh++ ;
- Mn %= 60 ; // prevent minute overflow
- Hh %= 24 ; // prevent hours overflow
- Delay ms(100) ; // debounce
- /*
- * prepare display buffer
- */
- /*
- * prepare time slot flags
- */
- Unsigned char s ;
- Unsigned char *p ;
- (*p).F0 = s.F0 ; // a segment
- (*p).F1 = s.F6 ; // g segment
- (*p).F2 = s.F3 ; // d segment
- (*p).F6 = s.F4 ; // e segment
- (*p).F7 = s.F5 ; // f segment
- P++ ; // next slot, center part of the digit
- (*p).F0 = s.F0 ; // a segment (continuation)
- (*p).F1 = s.F6 ; // g segment (continuation)
- (*p).F2 = s.F3 ; // d segment (continuation)
- P++ ; // next slot, right part of the digit
- (*p).F6 = s.F2 ; // b segment
- (*p).F7 = s.F1 ; // c segment
- ==Download project==
- Includes :
- * picoOSD C source code
- * picoOSD .HEX files
- ==Discussion and comments==
