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rikotech8
Joined: 10 Dec 2011
Posts: 376
Location: Sofiq,Bulgariq
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| display increasing value |
 Posted: Wed Apr 18, 2012 12:51 pm |
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Hello!
I'm using display - NHD-C0216CZ-FSW-FBW-3V3. The PIC is 16F873A.
I don't know particular driver to handle with this display, instead I use SPI communication, according datasheet.
The problem is to increasing given value. For example value = from '0' to '255'
Every time i need to combine several for cycles for every decimal digit and convert decimal to ASCII from the table where 1(dec)=49(ASCII) 2(dec)=50(ASCII).
Here is my pseudo code:
| Code: |
for(hundreds=0;hundreds<=9){
for(decades=0;decades<=9;decades++){
for(ones=0;ones<=9;ones++){
spi_write(hundreds);DDRAM++; //DDRAM++ mean shift_right
spi_write(decades);DDRAM++; //character possition
spi_write(ones);;
}
}
}
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If someone understand my problem, and know easier method to increase a value I would appreciate that. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Apr 18, 2012 1:57 pm |
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Get rid of that LCD. Get a normal LCD. Then, instead of spending weeks
on a simple program, you can spend minutes on it.
By using a normal LCD, I can write and test the whole program in about
1 minute. Here, it's done. The program displays this on the LCD:
| Code: |
0
1
2
3
4
5
6
7
8
9
10
11
12
.
.
.
98
99
100
101
.
.
.
250
251
252
253
254
255
0
1
2
3
.
.
.
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Here is the program to display an increasing value:
| Code: |
#include <18F4520.H>
#fuses INTRC_IO,NOWDT,PUT,BROWNOUT,NOLVP
#use delay(clock=4M)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#include "flex_lcd.c"
//======================================
void main(void)
{
int8 i;
lcd_init();
i = 0;
while(1)
{
printf(lcd_putc, "%3u", i);
i++;
lcd_gotoxy(1, 1);
delay_ms(200);
}
} |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19365
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| Posted: Wed Apr 18, 2012 3:05 pm |
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PCM programmer is right that a standard display is much easier to drive.
However, much worse, is the fact that the display you are listing, is _not_ compatible with the PIC you are using.
The PIC you have is a 5v device. Will work down to a minimum of 4v. The display is at heart a 3v device. It supports operation up to 4.4v _max_, but only guarantees it's high level output signal to go up to 2.4v, and it's inputs are only rated to go up to it's Vdd as a maximum. The command set is basically the same as for the normal LCD's, but the data is just sent using SPI, but you will be overdriving the display inputs to feed it from this PIC.
If you switch to a low voltage PIC, and operate at 3v, then you can actually just use the flex driver, with quite small modifications. Setting it up to not use read/write, and substituting the SPI write routine for the 'write_byte' routine, with a suitable setup_spi added to the init routine. This works, and all the standard flex_lcd functions run OK (lcd_gotoxy etc..).
Best Wishes |
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rikotech8
Joined: 10 Dec 2011
Posts: 376
Location: Sofiq,Bulgariq
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| Posted: Thu Apr 19, 2012 9:16 am |
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I use two individual voltages for both, via voltage regulators.
Thank you anyway. I keep punishing myself with that display because my job require like that.
Thank you again for the advice.! |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19365
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| Posted: Thu Apr 19, 2012 9:24 am |
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| rikotech8 wrote: | I use two individual voltages for both, via voltage regulators.
Thank you anyway. I keep punishing myself with that display because my job require like that.
Thank you again for the advice.! |
That doesn't solve the problem. The _output_ pins of the PIC will overdrive the _inputs_ of the display. Basically every time a pin goes high on the PIC, the only thing saving the display from destruction, will be the input protection diodes.....
Best Wishes |
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rikotech8
Joined: 10 Dec 2011
Posts: 376
Location: Sofiq,Bulgariq
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| Posted: Fri Apr 20, 2012 5:57 am |
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Yes, you are totally right. The constructor have put resistors(2,4K) between
transmission pins of a PIC and Display. This manipulation ought to protect the device from destruction. |
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