I came across some old LCD displays which wasn’t equipped with a display controller but only the LCD driver circuits. The label on the display read ‘LMG7410PLFC-A’ but I only got a hit matching ‘LMG7400PLFC’. This is the display which has the controller chip on and that datasheet are quite …
As a short follow-up on the giant clock that has been lying dormant for some time now, a video of the start-up pattern and initial settings of the clock is now available. When the clock is started, the digit controllers run through all the numbers and finally they start listening …
This is the code running on the segment driver controller boards: Main.c
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#include <htc.h> #define _XTAL_FREQ 8000000 #include "main.h" int address = 0x40; //address 0x10, 0x20, 0x30 or 0x40 __CONFIG(FOSC_INTOSCIO & WDTE_OFF); //internal osc. WDT off void interrupt isr(void) { if(RCIF) //handle incomming bytes { menu(RCREG); RCIF=0; //clear flag } } void main(void) { init(); //Setup ports test(); //Run segment tests number(7); //set value on display while(1) //let interrupts do the rest... {} } |
and Main.h (This is not the right way to do it)
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extern int address; int status=0; void number(int val) { switch(val) { case 0: PORTA=0x05; PORTC=0x0F; break; case 1: PORTA=0x05; PORTC=0x00; break; case 2: PORTA=0x06; PORTC=0x0D; break; case 3: PORTA=0x07; PORTC=0x09; break; case 4: PORTA=0x07; PORTC=0x02; break; case 5: PORTA=0x03; PORTC=0x0B; break; case 6: PORTA=0x03; PORTC=0x0F; break; case 7: PORTA=0x05; PORTC=0x01; break; case 8: PORTA=0x07; PORTC=0x0F; break; case 9: PORTA=0x07; PORTC=0x03; break; case 10: PORTA=0x00; PORTC=0x00; break; default: break; } } void test(void) { int j=0; for(j=0;j<11;j++) { number(j); __delay_ms(300); } PORTA=0x01; __delay_ms(100); PORTA=0x02; __delay_ms(100); PORTA=0x04; __delay_ms(100); PORTA=0x00; PORTC=0x01; __delay_ms(100); PORTC=0x02; __delay_ms(100); PORTC=0x04; __delay_ms(100); PORTC=0x08; __delay_ms(100); } void putch(unsigned char ch) { TXREG=ch; while((TXSTA&0x02)==0){} } void menu(char ch) { if (ch==0xAF) //packet start byte status=1; else if (status==1 && ch==address) status=2; else if (status==2) { number(ch); status=0; } else status=0; } void init(void) { //Osc OSCCON=0x70; //Ports TRISA=0xF8; //0,1,2 is output TRISC=0xF0; //0,1,2,3 is output //UART TXSTA=0x24; //Enable TX RCSTA=0x90; //Enable RX BRGH=1; BRG16=1; SPBRG=16; GIE=1; //Enable interrups PEIE=1; //Peripheral interrups RCIE=1; //receive interrupts } |
The nature of the project makes several controlling choices ‘the obvious choice’. The clock only needs 28 outputs for segments and 1 for the ‘dots’ in the middle of the clock (the option to turn them on and off is nice to have). finding a microcontroller with 29 outputs is …
This post will deal with the construction of the display segments. Not the individual strands of LEDs – they are done already. Instead the post will be about the casing that the segments will have. I started out by testing the Ledberg lamps (see previous post). Since it worked so …