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Hardware Uart in 9 bit mode [Solved]

 
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kmp84



Joined: 02 Feb 2010
Posts: 349

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Hardware Uart in 9 bit mode [Solved]
PostPosted: Thu Jul 27, 2017 2:29 pm     Reply with quote
Hello All,

I want to ask you if this is the right way to use hardware uart in 9 bit addressing mode.

Example:

Code:

#use rs232(baud=9600,rcv=PIN_C7,xmit=PIN_C6,bits=9,ERRORS,stream=B485)

#bit ninth_bit = RS232_ERRORS.7

byte TestPacket[] = {0x07, 0x01, 0x01, 0x00, 0x08, 0x1A, 0x00, 0x2B};


void SendDataToB(int8 *data, int8 len){
   int8 i;     
   
   for(i = 0; i < len; i++){
      if(i == 0)
         ninth_bit=1;
      else
         ninth_bit=0;
     
      fputc(data[i], B485);  // Send data
   }
}


I'm sending an example "TestPacket" but the device is not responding.
What could be the problem?

Thanks for attention!

Last edited by kmp84 on Thu Jul 27, 2017 3:01 pm; edited 1 time in total
Ttelmah



Joined: 11 Mar 2010
Posts: 19513

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PostPosted: Thu Jul 27, 2017 2:34 pm     Reply with quote
You don't have to.

Assuming a reasonably modern compiler, when set to 9bit mode, the getc, and putc instructions will accept a 16bit value, and handle the extra bit automatically (the functions are 'overloaded', and if they see a 16bit value, switch operation to handle this).
temtronic



Joined: 01 Jul 2010
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Location: Greensville,Ontario

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PostPosted: Thu Jul 27, 2017 2:44 pm     Reply with quote
I have a question...

You have 'stream=B485' in the USE RS232(...options...)

To me, that implies you're using an RS485 transceiver. If so, you also need to declare the 'control' pin for the TXX/RXD of the RS485 device. Unless it being used ONLY for one direction of data.

Also, if RS485 is being used, you need to use the correct pullup/pull down and termination resistors. These will be detailed in the RS485 device datasheet.

Jay
kmp84



Joined: 02 Feb 2010
Posts: 349

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PostPosted: Thu Jul 27, 2017 2:46 pm     Reply with quote
Hi Mr.Ttelmah,

How to handle 9 bit? Some example please?

Thanks,
kmp84



Joined: 02 Feb 2010
Posts: 349

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PostPosted: Thu Jul 27, 2017 2:55 pm     Reply with quote
temtronic wrote:
I have a question...

You have 'stream=B485' in the USE RS232(...options...)

To me , that implies you're using an RS485 transceiver. If so, you also need to declare the 'control' pin for the TXX/RXD of the RS485 device. Unless it being used ONLY for one direction of data.

Also, if RS485 is being used, you need to use the correct pullup/pull down and termination resistors. These will be detailed in teh RS485 device datasheet.

Jay


At the moment I'm using rs232 , but hardware also has and rs485 with this settings :

Code:

#use rs232(baud=9600,rcv=PIN_C7,xmit=PIN_C6,enable=pin_B2,bits=9,ERRORS,stream=B485)
temtronic



Joined: 01 Jul 2010
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PostPosted: Thu Jul 27, 2017 5:22 pm     Reply with quote
OK... what does the device use for communications? RS232 or RS485 ?? There is a BIG difference in the hardware AND then there's the software side to consider.
You cannot just connect a PIC up directly to the 'device', you need the correct interface chip(s).
If the 'device' is a commercial product, provide a link to the datasheet. That will help us.

'Not working' could be you've got a bare PIC tied to the device, you have TXD and RXD swapped, missing ground between devices, MAX232 tied to MAX485, and that's just a start of possibles....

Happy to help but I need more details about the project.

Jay
PCM programmer



Joined: 06 Sep 2003
Posts: 21708

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PostPosted: Thu Jul 27, 2017 7:37 pm     Reply with quote
Quote:
I want to ask you if this is the right way to use hardware uart in 9 bit addressing mode.

CCS gives examples of how to do this in the RS485.c file, in the drivers folder.

UART setup:
Code:
  #use rs232(baud=9600, xmit=RS485_TX_PIN, rcv=RS485_RX_PIN, enable=RS485_ENABLE_PIN, bits=9, long_data, errors, stream=RS485)


Look at this function in the RS485.c file:
Code:
int1 rs485_send_message(unsigned int8 to, unsigned int8 len, unsigned int8* data) {
.
.
.
}
kmp84



Joined: 02 Feb 2010
Posts: 349

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Problem Solved
PostPosted: Tue Aug 15, 2017 4:13 pm     Reply with quote
Hello All,

Sorry for my delayed response. I did not have for a long time PC and internet connection.
I have made successful communication in "9 bit long_data" format with hardware uart and also with software uart over physical rs232 and rs485.

Thank you very much !
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