Display One Wire text on GLCD

[panaos99]

Hi all,

I used to do PIC programming back in university and, I recently got myself an EasyPic v7a board to start again

So, I can display temperature ok using a DS1820 on the 16x2 LCD with the example OneWire code, however, when I change the code to show this on the GLCD, i only get zeros "00.00" instead of the actual temperature.
I have also attached a picture of this.
Everything else seems to work ok on the board (ports, switching on LEDs, creating rectangles on the GLCD etc.)

I am using the board's default PIC -PIC18F45K22 @ 8Mhz with a DS1820 temperature sensor with jumper 11 on RE2.

Thanks for the help!

Code: Select all

// PIC18F45K22 @ 8Mhz
// DS1820 Temperature sensor with jumper 11 on RE2

// Glcd module connections
char GLCD_DataPort at PORTD;

sbit GLCD_CS1 at LATB0_bit;
sbit GLCD_CS2 at LATB1_bit;
sbit GLCD_RS  at LATB2_bit;
sbit GLCD_RW  at LATB3_bit;
sbit GLCD_EN  at LATB4_bit;
sbit GLCD_RST at LATB5_bit;

sbit GLCD_CS1_Direction at TRISB0_bit;
sbit GLCD_CS2_Direction at TRISB1_bit;
sbit GLCD_RS_Direction  at TRISB2_bit;
sbit GLCD_RW_Direction  at TRISB3_bit;
sbit GLCD_EN_Direction  at TRISB4_bit;
sbit GLCD_RST_Direction at TRISB5_bit;
// End Glcd module connections

const unsigned short TEMP_RESOLUTION = 9;
char *text = "000.00  ";
unsigned temp;

void Display_Temperature(unsigned int temp2write)
{
 const unsigned short RES_SHIFT = TEMP_RESOLUTION - 8;
 char temp_whole;
 unsigned int temp_fraction;

 // check if temperature is negative
 if (temp2write & 0x8000)
 {
 text[0] = '-';
 temp2write = ~temp2write + 1;
 }

  // extract temp_whole
 temp_whole = temp2write >> RES_SHIFT ;

 // convert temp_whole to characters
 if (temp_whole/100)
 text[0] = temp_whole/100 + 48;
 else
 text[0] = ' ';

 text[1] = (temp_whole/10)%10 + 48; // Extract tens digit
 text[2] = temp_whole%10 + 48; // Extract ones digit

 // extract temp_fraction and convert it to unsigned int
 temp_fraction = temp2write << (4-RES_SHIFT);
 temp_fraction &= 0x000F;
 temp_fraction *= 625;

 // convert temp_fraction to characters
 text[4] = temp_fraction/1000 + 48; // Extract thousands digit
 text[5] = (temp_fraction/100)%10 + 48; // Extract hundreds digit
 //text[6] = (temp_fraction/10)%10 + 48; // Extract tens digit
 //text[7] = temp_fraction%10 + 48; // Extract ones digit

 // Display temperature on LCD
  Glcd_Write_Text_adv("Temperature:                 C", 3, 1);
  // Draw a circle with center in (50,50) and radius=10
  Glcd_Circle(92, 4, 1, 1);
  Glcd_Write_Text_adv(text, 65, 1);

 Delay_ms(1000);
}

int i=0;

void main()
{
TRISA = 0;
ANSELB = 0;                        // Configure PORTB pins as digital I/O
ANSELC = 0;                        // Configure PORTC pins as digital I/O
ANSELD = 0;                        // Configure PORTD pins as digital I/O

Glcd_Init();                       // Initialize GLCD
Glcd_Fill(0x00);                   // Clear GLCD
Delay_ms(200);

Glcd_Rectangle(0, 0, 127, 63, 1);
Glcd_Rectangle(1, 1, 126, 62, 1);
PORTA = 0b00000001;
Delay_ms(200);

 //--- main loop
 do {
 //--- perform temperature reading
 Ow_Reset(&PORTE, 2); // Onewire reset signal
 Ow_Write(&PORTE, 2, 0xCC); // Issue command SKIP_ROM
 Ow_Write(&PORTE, 2, 0x44); // Issue command CONVERT_T
 Delay_us(120);
 Ow_Reset(&PORTE, 2);
 Ow_Write(&PORTE, 2, 0xCC); // Issue command SKIP_ROM
 Ow_Write(&PORTE, 2, 0xBE); // Issue command READ_SCRATCHPAD
 temp = Ow_Read(&PORTE, 2);
 temp = (Ow_Read(&PORTE, 2) << 8) + temp;

 //--- Format and display result on Lcd
 Display_Temperature(temp);
 } while (1);

}  // end of program

[filip]

Hi,

Can you please attach detailed photo of your board ?

Regards,
Filip.

[panaos99]

Hi,

Can you please attach detailed photo of your board ?

Regards,
Filip.

Sure, I just took some pictures.
Anything specific to look for?

[hexreader]

Try the attached project, with a few changes made:

[panaos99]

Try the attached project, with a few changes made:

Thanks hexreader! That did the trick!
GLCD is now showing the temperature, with a bit of flash every 0.5 sec.
Do you mind sharing the changes you made in the code?

[hexreader]

Changes were:

1 ANSELE = 0; // PORTE digital, not analogue
2 box drawn over old number before new number drawn
3 PLL turned on and frequency box changed 8MHz to 32MHz - why run at 8 MHz when you can go at 32 MHz?
4 formatting improved

[hexreader]

If the flicker annoys you, then attached is a version that reduces flicker:

[panaos99]

Changes were:

1 ANSELE = 0; // PORTE digital, not analogue
2 box drawn over old number before new number drawn
3 PLL turned on and frequency box changed 8MHz to 32MHz - why run at 8 MHz when you can go at 32 MHz?
4 formatting improved

Thank you once more for the updated version below, very kind of you!

I was under the impression that if ANSEL is unimplemented, it reads as ‘0’ anyway, but in retrospect, I should have declared it anyway.

Didn't even know about the PLL, just did some reading in the PIC's manual. So, to enable this, we just enable the option in the "edit project" menu and set it at 32MHz? Is that all?

[hexreader]

Analogue capable pins are analogue at power-on

Datasheet will tell you POR (power-on-reset) values for all registers

we just enable the option in the "edit project" menu and set it at 32MHz? Is that all?

Yes, that is all there is to it

I have noticed that after a while, my GLCD corrupts.
Do not know why that should be
Does your GLCD work OK?

[panaos99]

Thank you for clarifying all these, very helpful!

My board is still running ok, no issues with the GLCD.

[hexreader]

Problem solved

Tried a different GLCD and all is well

Will mark first GLCD as "iffy" to prevent future confusion

[panaos99]

Problem solved

Tried a different GLCD and all is well

Will mark first GLCD as "iffy" to prevent future confusion

glad u sort it out.

I was looking into DS1820 manual, and it looks like its able to use an ADC with up to 12 bits. PIC18F45K22 has only a 10 bit ADC but I understand that we are only using 9 bits on this code, is that right?
is it possible to use the 10th bit as well?

[hexreader]

I was looking into DS1820 manual, and it looks like its able to use an ADC with up to 12 bits.

No, no, no.
DS1820 gives out a digital signal with nine bits of temperature resolution
DS18B20 can be set for 9, 10, 11 or 12 bits of resolution
Both devices are digital as far as the PIC18F45K22 is concerned. Interface pin must always be digital, never analogue

PIC18F45K22 has only a 10 bit ADC

This has no relevance. DS1820 gives out only digital signals

but I understand that we are only using 9 bits on this code, is that right?
is it possible to use the 10th bit as well?

DS1820 only sends 9-bit data so, code is adjusted for a 9 bit DS1820
You can adjust code for 10, 11 or twelve bits if you change to a DS18B20.

If analogue temperature sensor is of interest then fit an LM35 to your EasyPIC v7a into the TS2 socket
Note how TS1 socket is marked digital and DS1820, while TS2 is marked analogue and LM35

[panaos99]

Once more, thanks hexreader

In my attempt to show more digits after the decimal, I thought I was dealing with an analogue sensor.. Have no idea why I confused the two
I already tried the LM35, no issues there.

I will try and source a couple of DS18B20 sensors in the next couple of days, can you please guide me on how to adjust for 10+ bits of temperature resolution using the onewire function?

[hexreader]

Only one number in one line of code to change:

Code: Select all

const unsigned short TEMP_RESOLUTION = 12;                                      // select 9 for DS1820, 12 for DS18B20