serial port sending/receiving to/from pic and pc

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i have
PortB(pins RB0 through RB7)of the pic16 defined as an input with a dip switch connected to it
PortD(pins RD0 through RD7)as output each connected to a LED,also each pin of PORT B corresponds to one from PORT D

how can i configure that this port is the input and output in the first place and it's supposed to be configured in the pic code? or in the c# application? i think it 's supposed to be in the pic program. but i'm just wondering

when reading from the microcontroller i want to read the status of the 8 output LEDS once or i can collect them, how is that possible?

and i want to be able to control the status of these leds using my c# program but i have an issue on how to receive their status and set it later .

i tried reading but it was on port A not on the output(port d)
i'm using proteus to stimulate the circuit and a comport virtual emulator and to write the code of the pic mikroc (i'm new to it most of the codes i got from the internet and i kinda understood)
i just want to know how to read the status of port D like (101011) pr something like that and how to set each pin of portD if that's possible

i'm still new to all of this i'm just trying my best ,
excuse my lack of knowledge ,afterall i'm still learning .
please, and Thanks !:)

my c# functions code to read and write

SerialPort port ;
void Pread()
{
    port = new SerialPort("COM2", 9600, Parity.None, 8, StopBits.One);
   // port.ReadTimeout = 500;
    port.DataReceived += new SerialDataReceivedEventHandler(DataReceivedHandler);
    port.Open();


}

private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
    SerialPort port= (SerialPort)sender;
    string w = port.ReadByte().ToString();
    if (w != String.Empty)
    {
        Invoke(new Action(() => richTextBox1.AppendText(w))); //it will read and append the reading to a richtextbox
    }
}

void Pwrite(string num)
{
    port.WriteTimeout = 500;
    port.Open();
    port.WriteLine(num.ToString());
    port.Close();
}

private void button1_Click(object sender, EventArgs e)
{
    Pread();
}

Posted 24-Apr-14 7:03am

Duaa7

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Comments

gggustafson 24-Apr-14 13:42pm

Which PIC16 microchip are you using?

Duaa7 24-Apr-14 13:46pm

pic16f877a sorry for not mentioning it!

gggustafson 24-Apr-14 16:06pm

Paraphrasing the documentation Microchip PIC16F87XA Data Sheet (http://ww1.microchip.com/downloads/en/DeviceDoc/39582C.pdf), PORTB is an 8-bit wide bidirectional port. Data direction is defined by data direction register TRISB. Setting a TRISB bit (= 1) will make the corresponding PORTB pin an input. Clearing a TRISB bit (= 0) will make the corresponding PORTB pin an output pin.

Four of the PORTB pins, RB7:RB4, have an interrupton-change feature. Only pins configured as inputs can cause this interrupt to occur (i.e., any RB7:RB4 pin configured as an output is excluded from the interrupton-change comparison). The input pins (of RB7:RB4) are compared with the old value latched on the last read of PORTB. The “mismatch” outputs of RB7:RB4 are OR’ed together to generate the RB port change interrupt with flag bit RBIF (INTCON&lt;0&gt;).

The interrupt-on-change feature is recommended for wake-up on key depression operation and operations where PORTB is only used for the interrupt-on-change feature. Polling of PORTB is not recommended while using the interrupt-on-change feature.

So, from what I read, you can be notified of a change in 4 of the 8 DIP switches using interrupts. But if you need to detect the changes in all 8, you must use polling. And if you use polling, you may not interrupt-on-change feature. And you appear to be right: the setup must be made using PIC16 code.

PORTD is an 8-bit port. Each pin is individually configurable as an input or output.

Here I am a little confused by your question. I was assuming that the DIP switches on PORTB would control the LED segments on PORTD. Maybe you could supply a little more information on how the DIP switches and LED segments are wired and how the PC interacts with the PIC16 (through serial port?).

Duaa7 25-Apr-14 17:08pm

//drive.google.com/file/d/0B6NPKZsgNLOCVHE1RWF4dzNOWnM/edit?usp=sharing
that's the circuit i built using proteus I want my c # program to be able to change the status of a pin in portD (but i'm wondering portD is receiving the 1 bit from portB or from the serial port now) so if its receiving it from portb its like i'm changing the value of the pin on port b to be able to change the value on portD,the pc will be interacting with the pic with through the c# code it's not totally done i'm just trying to receive the values of port D and send the values from the pc to portD now and when this is all good i'll try to improve the way it works by adding a thread that will continuously be reading the values

GUI will be such as showing the full map of the floor with red/green symbols in each room representing light and Air conditioning ( AC: heater/cooler) . Green means ON that and RED means OFF (one symbol for lights and one symbol for AC in each room).
The status of these symbols will be later on acquired from the microcontroller ( real field) which will keep sending this info to the computer through com port serial interface

On another hand the computer software will be :
1) Calculating the total energy in all the floor and take action if the total Current is above a certain threshold.
(The action would be to switch off AC and/or Light in one on more room.)

2) Developing a time schedule that will also dictate time range of switching On and OFF the AC or Lights.

After processing the first 2 above conditions, if any change in the status is required The computer software will change the status and send the command to the microcontroller.

i still haven't done any of them and i'm still in the first step
https://drive.google.com/file/d/0B6NPKZsgNLOCNVRaaHY3QmNpZVU/edit?usp=sharing
https://drive.google.com/file/d/0B6NPKZsgNLOCRjRfMzF4bE4wSUU/edit?usp=sharing
that's the c# program and the points will be shown according to the status of the portd pins
i hope everything is clear

gggustafson 25-Apr-14 17:44pm

I can access the drawing in the first link. However the last two links are protected. I've applied for permission to look at them. We will have to wait.

Duaa7 25-Apr-14 19:25pm

i didn't notice that i didn't set their privacy to be public , thank you so much and thanks for you patience

gggustafson 26-Apr-14 12:10pm

What I think you are trying to accomplish: PORTD bits are set by the PC (serial port) through TXD; DIP switches connected to PORTB are only a manual way to set the bits.

I do not see any internal PIC16 connections (i.e., you have not provided software that controls the PIC16).

How do you interconnect PORTB to PORTD? How do you interconnect TXD to PORTD (you will have to test the incoming serial port message and set the bits of PORTD appropriately)?

How do you avoid race conditions between PORTB and TXD?

Which has greater precedence: DIP switches connected to PORTB or signals coming from TXD?

What is the protocol that you will use on the serial port? Just sending bits is not sufficient. The PC and the PIC16 must agree on what will be sent by each side; otherwise there will be chaos.

I am not an EE so I cannot comment on your circuit. But isn't there supposed to be some kind of interface between the PIC16 and the LEDs? Doesn't something have to provide power to the LEDs?

I am now going to be somewhat harsh. Do not take it personally.

Building a home (or office) automation system is an area for X10 devices and standards. Building a toy is fun and has no such restrictions as standards. I fear that your project is not real. It may be an educational experience but so far you have not considered communicating with the controlled devices. You have not considered the PC drivers needed to control devices. For EE education purposes that is fine. But in the real world, you do not need any hardware. By buying a few parts and writing a GUI, everything can be done on the PC.

Good Luck.

Duaa7 26-Apr-14 17:51pm

yes what you have said is true . 
 
the interconnection of portB and D is in the pic's program code yes. 
 
yeah i know it's not real ,don't worry, its alright i get it ,it's just being built for educational purposes and to get working with microcontrollers no more ,it is a project and i 'm responsible for the program and how it'll communicate with the pic although i don't have the real circuit so i can't really test everything but the stimulation is enough i guess ,and thank you for asking these questions i may have thought about them and totally forget later on ,but i thought all of these details should be included in the 
pic's code not in the c# program ,isn't true? 
 
 
what concerns me is how to handle the data that the pic will be sending me and to know in what format they will be and how will i send the data in return and their format . and to make my program as useful as it can be from the side of communicating with the microcontroller through sending and receiving 
about the circuit it's not complete it's not going to be implemented this way i'm just trying to see how it might work a lot of the connections aren't there 
 
anyway,thank you so much

gggustafson 26-Apr-14 23:48pm

Here's what I think your approach should be:

Obtain and install (on your PC) a PIC16 development environment. Should include a cross compiler and loader so that you can develop software on the PC and download it to the PIC16. Note that the development kit will be used for the PIC16, not the PC GUI. Microchip appears to be a good source. You might even contact their support organization and inquire as to what they would recommend that you obtain and any suggested references.

Get a good book on microchip software design.

On the PC side it is recommended that you develop a device driver. For that you need to get the Microsoft DDK (I'd also get the SDK). These are the tools that will let you build a device driver. I strongly recommend that you stay with user-mode drivers. Kernel-mode drivers can cause serious damage to your PC. Read the online documentation regarding development of device drivers.

On CP, find the article "Writing a Sensor Driver for the Wiimote on Windows 7" and study it well. It will give you some idea as to how to process you input from the PIC16.

There is no simple way to achieve what you want. Again, good luck.

Gus

Duaa7 27-Apr-14 13:11pm

i have mplab installed now and will see what i can do about the other stuff
but Thank you very much !:)
i hope you'd have a great day.

gggustafson 27-Apr-14 13:22pm

Good choice. It appears pretty good especially since it was developed by the PIC16 manufacturer. Come back if we can help.

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