Sample code of PR11 does not work on PIC16F877a

[TeoYX]

I need the confirm to this pin connection. From the sample source code, it is as output. Does it correct?

[altron11]

Hi Guys,

Now i would like to use PORT E as output to a LED.

DO i need any special codings? As i already set TRISE=0b00000000;
But the PORT E0 does not have any output.

[robosang]

I need the confirm to this pin connection. From the sample source code, it is as output. Does it correct?

Curious to know, which part of the code showing that RA3 as output? I thought that is Vref pin? Though I din study this DIY project from Cytron much, but did went through the schematic before. I don think it is output.

Now i would like to use PORT E as output to a LED.

DO i need any special codings? As i already set TRISE=0b00000000;
But the PORT E0 does not have any output.

Who say PORTE does not have output? Every PORT can be input and output, and how come PORTE is not?

[TeoYX]

From the source code:

void main(void)
{
ADRESH=0; //clear A/D result
ADRESL=0; //clear A/D result

//setting ADCON1 Register
ADCON1=0b11000101; // A/D result right justified,
// configure RA2 and RA5 as digital I/O

TRISA=0b11011011; //configure PORTA I/O direction
TRISB=0b00000000; //configure PORTB as output
TRISC=0b00000000; //configure PORTC as output

PORTA=0;
PORTB=0;

Above are parts of the program... Do u know why?

[altron11]

Hi Guys,

I have a circuit simliar to the PR11. The sensor(LM35) connection is the same with a capacitor series to gnd. On my project board, it is working. But after i soldered up every component, the readings from the sensor shoot as high as 60deg upon power up. Is there anything wrong?

[zhenning]

Hi Guys,

I have a circuit simliar to the PR11. The sensor(LM35) connection is the same with a capacitor series to gnd. On my project board, it is working. But after i soldered up every component, the readings from the sensor shoot as high as 60deg upon power up. Is there anything wrong?

Most likely something is wrongly connected on your hardware :0

[altron11]

I guess not as it is very similar to the PR11. Difference is my PIC is on the SK40-C and i soldered the LCD onto the SK40-C. I connect RA0 to the Vout pin of the LM35. V+ to the VCC (5V) and a 0.1uF Cap in series from Vout to GND. now the temperature fix at 31deg. it will not increase or decrease. I do have a question, do i still need to connect a variable resistor of 4.7k ohm to the Vref+? thats the only thing i missed out.

[robosang]

void main(void)
{
ADRESH=0; //clear A/D result
ADRESL=0; //clear A/D result

//setting ADCON1 Register
ADCON1=0b11000101; // A/D result right justified,
// configure RA2 and RA5 as digital I/O

TRISA=0b11011011; //configure PORTA I/O direction
TRISB=0b00000000; //configure PORTB as output
TRISC=0b00000000; //configure PORTC as output

PORTA=0;
PORTB=0;

Woh.... you cannot paste a source code and ask why, I am sure no one will entertain you. Furthermore there is already comments at back of most line. You need to highlight which part you don understand, if you don understand all, please go back to the datasheet, I am sure will be able to find what is ADCON1, PORTA, TRISA, ADRESL...etc

Btw, I din see any code saying PORTE is output, that is my earlier question. Curious to know where you get conclusion that PORTE is output. I think this sample code that you refer is using smaller PIC, maybe 28-pin and now you are using 40-pin. Of course in 28-pin the program cannot configure pins that do not exist. Yet, you are using 40-pin now, but do you use it? If you don use it, ignore it.

[robosang]

I guess not as it is very similar to the PR11. Difference is my PIC is on the SK40-C and i soldered the LCD onto the SK40-C. I connect RA0 to the Vout pin of the LM35. V+ to the VCC (5V) and a 0.1uF Cap in series from Vout to GND. now the temperature fix at 31deg. it will not increase or decrease. I do have a question, do i still need to connect a variable resistor of 4.7k ohm to the Vref+? thats the only thing i missed out.

I think I answered this some thread before. If the code is using Vref+ and hardware is not connected with proper Vref+, you will have problem. I din go to check the PR11 code nor the schematic, yet seeing your explain, you will need to provide Vref+. Again, curious to know why don just put that circuit in?

[altron11]

I guess not as it is very similar to the PR11. Difference is my PIC is on the SK40-C and i soldered the LCD onto the SK40-C. I connect RA0 to the Vout pin of the LM35. V+ to the VCC (5V) and a 0.1uF Cap in series from Vout to GND. now the temperature fix at 31deg. it will not increase or decrease. I do have a question, do i still need to connect a variable resistor of 4.7k ohm to the Vref+? thats the only thing i missed out.

I think I answered this some thread before. If the code is using Vref+ and hardware is not connected with proper Vref+, you will have problem. I din go to check the PR11 code nor the schematic, yet seeing your explain, you will need to provide Vref+. Again, curious to know why don just put that circuit in?

Hi robosang,

Thanks for the advise. I found out that I had a open connection thats why it is not measuring.
I overlook on this while i tested on a project board and it works thus i did not soldered up to the Vref+. I had done it.