Comments on: Interfacing LCD via SPI.

By: afzal khan

afzal khan — Wed, 04 Aug 2010 13:51:58 +0000

m also having a graphic lcd ogm 128*64, plz provide me the schematic to connect it by the serial connection i.e spi…

thank you so much

By: afzal khan

afzal khan — Wed, 04 Aug 2010 12:01:48 +0000

sir we are using at32uc3a (atmel 32 bit ) which supported spi bt sir at lcd therer are 16 pins/20 pin but how can we know that they will support spi .sir i have an lcd 20into4 JHD 204A .if u have any schematic or project please provide me schematic…thanks for your reply

By: afzal khan

afzal khan — Wed, 04 Aug 2010 06:37:27 +0000

hello sir is this possible to make any lcd to support spi mode through the hardware connection….because all lcd have same pin and drivers…so is it possible to spi with do -d7 pins

By: oleg

oleg — Tue, 27 Apr 2010 17:21:34 +0000

In order to print something, you need to clear the screen. Do this in main() -> insert LCD_Home(); before while( 1 ); you shall get blank screen. To print a string, define it like strings “hello” and “second_line” at the beginning of SPI_LCD.c and then print it using LCD_send_string().

SPI_LCD.c

…
const rom char *const rom temperature = “TEMP = “;

….

void main( void )
…

LCD_Home();
LCD_send_string( temperature );
LCD_send_hexbyte( ReadADC(0) );

while( 1 );
}

By: Tom

Tom — Tue, 27 Apr 2010 07:16:21 +0000

So far i built your entire project and got the hello world sent to the screen and everything!!! good work i learned a lot

I am now trying to send a reading to the LCD say Its an ADC value is this how i would send it? Let me know where i have gone wrong, using ReadADC(0) as my value,

void LCD_send_hexbyte ( BYTE ReadADC(0) )
{
BYTE temp = ReadADC(0)>>4; //prepare first output character

if ( temp > 9 ) temp+=7; //jump to letters in ASCII table
LCD_sendchar ( temp + 0×30 );

ReadADC(0) = ReadADC(0) & 0×0f; // mask 4 high bits
if ( ReadADC(0) > 9 ) data+=7;
LCD_sendchar ( data + 0×30 );
}

Also what if i wanted my screen to read TEMP = ( the ADC VALUE here ) how would i manage that?

By: oleg

oleg — Thu, 08 Apr 2010 02:41:39 +0000

VCC is VDD, VSS is GND. You need capacitors between pins 11,12 and 31,32.

AFAIK PIC18F452 doesn’t have internal oscillator. You will need to build an external one. It will be hard to make it work well on a breadboard.

By: Dinnin

Dinnin — Thu, 08 Apr 2010 02:33:13 +0000

Ok i just want to clarify, I need a cap between VDD and VCC on the pic18f452, on both sides? and do i also need one between both VSS and ground? Just wondering b/c in your picture it looks like the cap is between pin 11 and 12 which is VDD and VSS. And this is different from you schematic and i dont want to mess this up since i am mid build.

Also i have the pic18f452 I/P will that work for this build? I do not know the difference?

Thanks for you help sorry if the questions are trivial.

By: oleg

oleg — Wed, 07 Apr 2010 17:14:42 +0000

0.1uF capacitors are recommended by spec between VCC and ground, in case of 18F452 between both VCCs and ground (there is another VCC pin on the other side ). VCC voltage can be 5V or 3V – it depends on your LCD contrast bias more than anything else. If you have 3.3V-rated LCD(not common), use 3.3V at VCC, otherwise use 5V.

By: Dinnin

Dinnin — Wed, 07 Apr 2010 17:03:58 +0000

I noticed a few things on the picture and your schematic and had a few questions.

First in the picture you have what looks like a capacitor between pin 11 and 12 on the pic18 but its not in ur schematic. If there is one there what is its value?

Also how much voltage does the SPI require i noticed you have the same VCC for the LCD and the SPI is that 5V? 3V? just curious b/c i am planning on building this and wanted to do it right!

By: oleg

oleg — Tue, 16 Mar 2010 22:55:10 +0000

Microchip LCD library functions won’t work with this circuit