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PSoC 4 MCU

ShVy_264716
New Contributor II

Hey All

   

Wishing all of you and your families  a very happy and prosperous new year in advance !!!

   

Anyone one working or has worked on UART? I need a task to be accomplished as below:

   

- PSoC4 should receive a character string and store it in an array.

   

- The programming should be interrupt based, specially with UART Rx interrupt and no delays included.

   

For example, let us assume I am receiving a character string "OK\n". On receiving the entire string, I should come to know that the entire string has been received. I will compare that string with a setpoint string "OK\n". If both match, an LED should blink.

   

 

   

Regards

   

Shaunak

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30 Replies
ETRO_SSN583
Esteemed Contributor

There is a UART Rx project in example projects, the Rx ISR is

   

enabled in properties, however in the project itself the ISR is not

   

"doing anything". Should be simple to add your code into that

   

ISR (there are place holders for your code so it does not get over-

   

written on compile, example below). Remember to declare global

   

variables volatile that are used in your ISR.

   

 

   

        /* User code required at start of ISR */
        /* `#START UART_1_RXISR_START` */

        /* `#END` */

   

 

   

Regards, Dana.

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JoMe_264151
Expert II

The last character of the string is "\n" which is 0x0a in ASCII. When you buffer your string (could be a circular buffer) you can signal the controlling program that a complete string has arrived.

   

-Mark begin of string

   

-Get character.

   

-When character is \n store 0x00 (end-of-string indicator) and signal "String received" else store character and loop

   

 

   

 

   

Bob

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odissey1
Honored Contributor II

Attached is example  project of using UART for receiving commands. It utilizes non-blocking circular buffer to receive characters from UART Rx and split them into command messages when termination characters are found (0x0D and/or 0x0A). Project closely follows code posted by Bob Marlowe before. This demo shows how to change colors of the LED on the PSoC4 PioneerBoard.

   

Each received message has one "command" byte followed by "value string":

   

<cmd><value string> <\r> [<\n>], example: R255\n (set red LED to 255).

   

 If one <cmd> byte is not enough for your commands, change it to 2 (or more).

   

Note that in this project UART rate was set to 230k to match speed  of my Bluetooth HC-05 dongle. Change it to your own UART rate.

   

odissey1

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ShVy_264716
New Contributor II

Thank you everyone for giving solutions, though I am still not getting results. Please share a project that works with UART Receive interrupt configured such as an interrupt is generated each time a byte is received.

   

Thanks in advance.

   

 

   

Regards

   

Shaunak

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JoMe_264151
Expert II

The project Odissey1's posted contains some usable code, why don't you base on that or do you have got any other difficulties?

   

 

   

Bob

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odissey1
Honored Contributor II

Shaunak,

   

in my project, interrupt is fired on every char received, but then characters go into receiving buffer for further processing when CPU is available. This way UART will not interrupt processes run by the CPU. This is the way simple UART input should operate...

   

 

   

If you don't need complex command structure, just replace processing portion in the above project with:

   

 

   

void ProcessCommandMsg(void)

   

 

   

 {

   

     //check received message for valid command

   

 

   

     if (RB.RxStr == 'OK') // 'OK' string received..     

   

     {

   

          \\do something...

   

      }

   

 

   

}

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ShVy_264716
New Contributor II

Thank you all for support. I am sorry I replied late as I was having some other tasks on plate. Check my next post on this thread only, that discusses the GSM SIM300 related project.

   

 

   

Regards

   

Shaunak

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ShVy_264716
New Contributor II

Bob, Dana and Odissy

   

Thanks for your support. Actually I am working on GSM SIM300 module interfacing with PSoC4 and developing project for sending and receiving messages on certain events. In this project, I need to take care of the timeout feature also. If any of all of us has worked on GSM SIM300, he/she can help me out with this. For those who have not worked on it, I have a SIM300 library for AVR microcontroller that I found while searching on internet. I believe we all can do the analogy of PSoC4 with AVR and have a complete GSM solution, which is never done as far as I know. Please find attached the entire project targetted to AVR based on C language. The developer of the project is Mr. Avinash Gupta. Here is the link that explains the project:

   

http://extremeelectronics.co.in/avr-tutorials/sending-an-receiving-sms-using-sim300-gsm-module/

   

Please go through this project and let this thread be live through open discussion and development for GSM SIM300 with PSoC4.

   

 

   

Regards

   

Shaunak

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ShVy_264716
New Contributor II

Can anyone please explain how to write UART receive interrupt service routine and clear the UART Rx FIFO not empty interrupt? Currently I am sending "AT" command to the GSM SIM300 Module and want to receive "OK" in return. But I am not getting desired results. When I debugged it, I came to know that my code does not come out of UART Interrupt service routine. Please find attached my project.

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JoMe_264151
Expert II

Hi Shaunak!

   

Just use

   

    ch = UART_UartGetByte();
    UART_ClearRxInterruptSource(UART_INTR_RX_NOT_EMPTY);
 

   

Dangerous is the use of a global variable named ch which can be overlooked/overwritten easily. Additionally it should be declared to be volatile since it is changed in an interrupt handler.

   

You write data to the LCD. This should not be done in an interrupt handler because you may run into troules later when the project grows: Writing to LCD contains some delays which will hinder any other interrupt to be handled until this interrupt finishes. That could be a remarkable time making other parts of the progem to fail.

   

Usually the structure of an interrupt-driven receiver just reads-off the character and saves it in a buffer, clearing the interrupt and optionally setting a flag indicating a char received or found an end-of-message,. In the main-loop the flags are checked and acted upon them. 

   

 

   

Bob

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ShVy_264716
New Contributor II

Hi Bob!

   

Thank you. It works now as per your suggestions.

   

Regards

   

Shaunak

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JoMe_264151
Expert II

Shaunak, you are always welcome!

   

 

   

Bob

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Anonymous
Not applicable

Hi people.
In first time sorry to write this question in this post. I am newly
1º) how do i open new thread?

   

2º) my question is: I try to communicate (In basic form) the UART block with the Hyperterminal. if I put  UART_1_UartPutString("Ejemplo") I recive (in Hyperterminal) ASCII noise. No the word Ejemplo

   

then how i solve this?

   

very thanks for your patience and time

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JoMe_264151
Expert II

Welcome in the forum!

   

Check the baud-rate selected for HyperTerminal and your UART, must be the same.

   

 

   

Bob

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Anonymous
Not applicable

Thanks bob for your fast answer.

   

I attach capture with all information.

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JoMe_264151
Expert II

Has the Hyperterminal program got a baud selection? Can you post your complete project, so that we all can have a look at all of your settings? To do so, use
Creator->File->Create Workspace Bundle (minimal)
and attach the resulting file.

   

And please tell us which board exactly you use.

   

 

   

Bob

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Anonymous
Not applicable

I follow the steps in element14 web (USB-UART utility proyect)

   

and the same result, noise ascii.

   

I download the zip and programed it into the board, the echo program work bad ( if I push the number 5 in the keyboard, appear a triangle simbol)

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JoMe_264151
Expert II

Can you post your complete project, so that we all can have a look at all of your settings? To do so, use
Creator->File->Create Workspace Bundle (minimal)
and attach the resulting file.

   

And please tell us which board exactly you use.

   

 

   

Bob

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Anonymous
Not applicable

My intention is when i push SW2 button the LED ( included in the board) it turn on and at the same time I wanna see in the terminal some text.Also put some character by keyboard (and receive echos like feedback)

   

Programming started for device: 'PSoC 4200 CY8C4245AX*-483

   

PD:I Sorry by dirt code

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JoMe_264151
Expert II

I asked for the board, not for the chip (which I could take from the project).

   

I assume you are using a CY8CKIT-042 Pioneer kit.

   

 

   

Bob

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JoMe_264151
Expert II

The OutputString should be a bit more generous, use [20] to be on the safe side.

   

You read from UART outside of the "if (switched pressed) but a character received != 0 is not saved and will get overwritten.

   

The switch will read 1 when not pressed and 0 when pressed.

   

So the logic is that your 35678 is printed over and over again

   

What external connections did you make? You have to provide 2 wires to connect to the KitProg part on the board.

   

You need to enable interrupts globally (CyGlobalIntEnable) when using PrintString()

   

 

   

Bob

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JoMe_264151
Expert II

Wire connections to make look at the picture

   

 

   

Bob

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Anonymous
Not applicable

yes, CY8CKIT-042 Pionner Kit, and Creator3.3, Win 10.

   

Very Thanks for your time

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Anonymous
Not applicable

Hi bob..
Very thanks for you collaboration , with out you will be impossible.

   

thanks for your time and patience...

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JoMe_264151
Expert II

Thank you, you are always welcome!

   

The "noise" you see at the screen of PuTTY comes from the open UART-bridge Rx input, so when the chip runs more noise is produced.

   

 

   

Bob

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Anonymous
Not applicable

Hi , bob. The Code and Putty work perfect. but the same code not work in Hyperterminal  (make a infinite loop Ascii noise).

   

I attach the final code.

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Anonymous
Not applicable

really not is a noise, is a loop of same ascii string .
like this:

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JoMe_264151
Expert II

PuTTY and Hyperterminal both just display what they get. When there is a difference in the programs it must be in the setup of  one of these programs.

   

 

   

Bob

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Anonymous
Not applicable

Hi guys!

   

How to implement an check 'OK' string if response is arrived actually to my cypress?

   

MAIN

   

uint32 rxData;
    
    UART_Start(); // ZigBee module
    PWM_Start();
    
    UART_ClearRxBuffer();
    UART_PutString("AT\n\r");
       
    FOR
        rxData = UART_GetChar();
        if(rxData){
            CyDelay(2000);
            PWM_Stop(); //control LED status

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Anonymous
Not applicable

Some of the posts at the beginning of this thread walk through/explain how to do it using the example project

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