Issue with UART and Xbee

Alex Mtnez

Other Parts Discussed in Thread: CONTROLSUITE

Hi all, I bought a TSM320F2062, i am interfacing with xbee by sci-a port. I'm using the example proposed by ControlSuite, called SCI_echoback. As you know Xbee has two modes, either AT or API.

First I modified the example, and I make my own "hello world" in AT mode with twice xbee (they are configured correctly). if i send a message, always in AT mode, transmission works fine, I can be able to receipt or send any command. But, in API mode, it's impossible. I can't send anything, except one time, it's works.

I suposse All registers, are correctly configured, because in AT mode works fine. I tried several uart speed (setting SCIxBAUD), with no difference. Also, sniffing SCia I can see the correct API frame, like 7E 00 05 08 01 50 31 04 71.

baud rate is 9600, no parity, 8bit word, no handshake and one stop bit.

some advice?

Best regards

Alejandro

over 12 years ago

0 Maria Todorova over 12 years ago

Guru 13185 points

Hello Alejandro,

Do you use interrupt for your code?

Can you send the code for the SCI setting and about how you send command and receive the data?

Hope somebody can notice the problem on your SCI.

Best regards,

Maria

0 Alex Mtnez over 12 years ago in reply to Maria Todorova

Prodigy 115 points

Hi Maria,

i'm not using interrupts (not yet), just make a for(;;) sending a continuos msg.

To send, I modified the example mentioned above, sci_echoback

for(;;) {

msg_frame[0] = 0x7E; // 7E
msg_frame[1] = 0x00;//\x00'
msg_frame[2] = 0x05;//'\x05'
msg_frame[3] = 0x08;//'\x08'
msg_frame[4] = 0x01;//'\x01'
msg_frame[5] = 0x50;//'\x50'
msg_frame[6] = 0x31;//'\x31'
msg_frame[7] = 0x04;//'\x05'
msg_frame[8] = 0x71;//'\x70' checksum

char j = 0;
while (sizeof(msg_frame) != j) {
scia_xmit(msg_frame[j]);
j++;
}

void scia_xmit(int a)
{
while (SciaRegs.SCIFFTX.bit.TXFFST != 0) {}
SciaRegs.SCITXBUF=a;

}

The question is: why in AT mode I can send whole commands and not in API mode?

Best regards

0 Maria Todorova over 12 years ago in reply to Alex Mtnez

Guru 13185 points

Hello Alex,

What is your SCIFFTX setting?

How about if you remove line 'while (SciaRegs.SCIFFTX.bit.TXFFST != 0) {}' ?

And what is the difference between your code above and AT code? Is the difference only the data?

Best regards,

Maria

0 Alex Mtnez over 12 years ago in reply to Maria Todorova

Prodigy 115 points

removed line "while(sciaRegs.........." no difference. Yes, in AT data is ASCII characters and API are hex.

it needed reset SCI before to send a message?

0 Maria Todorova over 12 years ago in reply to Alex Mtnez

Guru 13185 points

Hello,

I think you don't need to reset the SCI.

Seems that your transmit is fine if you can get 7E 00 05 08 01 50 31 04 71 (you said you sniffed the SCIA and got this result).

What is the type of msg_frame? Is it unsigned char?

What result do you expect in your application?

Best regards,

Maria

0 Maria Todorova over 12 years ago in reply to Maria Todorova

Guru 13185 points

Hello again,

How about you try the setting without FIFO?

1. Setup GPIOs for SCIA
2. Init SCIA (modify it based on your setting)
   SciaRegs.SCICCR.all =0x0007;   // 1 stop bit, No loopback
                                   // No parity,8 char bits,
                                   // async mode, idle-line protocol
   SciaRegs.SCICTL1.all =0x0003; // enable TX, RX, internal SCICLK,
                                   // Disable RX ERR, SLEEP, TXWAKE

   SciaRegs.SCICTL2.bit.TXINTENA = 1;
    SciaRegs.SCICTL2.bit.RXBKINTENA = 1; // actually you don't need this


   SciaRegs.SCIHBAUD    =0x0001; // 9600 baud @LSPCLK = 20MHz (80 MHz SYSCLK).
       SciaRegs.SCILBAUD    =0x0003;

   SciaRegs.SCICTL1.all =0x0023; // Relinquish SCI from Reset
}

4. in for loop:
for(;;) {
   msg_frame[0] = 0x7E; // 7E //the type of msg_frame is unsigned char
   msg_frame[1] = 0x00;//\x00'
   msg_frame[2] = 0x05;//'\x05'
   msg_frame[3] = 0x08;//'\x08'
   msg_frame[4] = 0x01;//'\x01'
   msg_frame[5] = 0x50;//'\x50'
   msg_frame[6] = 0x31;//'\x31'
   msg_frame[7] = 0x04;//'\x05'
   msg_frame[8] = 0x71;//'\x70' checksum

   unsigned char i;
   i = 0;


   for(i = 0; i < (sizeof(msg_frame)); i++)
   {
       SciaRegs.SCITXBUF = msg_frame[i];
   }

}

Let see whether this works.

Best regards,

Maria

0 Alex Mtnez over 12 years ago in reply to Maria Todorova

Prodigy 115 points

Hi Maria, finally works fine, I guess is a issue with zigbee xbee module. by the way, I've seen the function UARTprintf(); but I can't use it. I tried add uartstdio.c and uartstdio.h but doesn't works.

how add the files correctly?

0 Gautam Iyer over 12 years ago in reply to Alex Mtnez

Guru 192875 points

Hi Alex,

Check these threads out:

http://e2e.ti.com/support/microcontrollers/c2000/f/171/t/128230.aspx

Regards,

Gautam

C2000™︎ microcontrollers

C2000 microcontrollers forum

Issue with UART and Xbee