[Efi332] Queued SCI transmit with interrupts on MPC555

[David Eicher]

Hi John,

Thanks for your response. Yep, I'm trying to get the QSCI to work on the
MPC555 for transmit. I've just got a block of data I need to transmit.

I've implemented the code per the demo code in the quickstart package, it
just flat does not work for me. I've tried both use the two interrupts (QBHE
and QTHE), and tried just using the QBHE interrupt alone (filling queue with
16 bytes each time), and had no success for many hours.

Just earlier tonight I finally managed to get one approach to the point it
appears it is working (more testing required yet though). I'm using just the
QBHE interrupt and flag, filling the queue with 16 bytes each time. The demo
code does not include a "set QTE and TE" in the ISR after the queue is
loaded, but it doesn't seem to transmit without it. There is nothing I've
found in the users manual for MPC555 that indicates that this is required,
but I've had to keep turning the queue on over and over again to keep it
transmitting. 

Is this correct? Or am I just bandaiding some error in my code with the
setting of QTE and TE?

I"ll include the code I've found that works, I'd appreciate your comments on
it:

Thanks much,

Dave

--------------------------------------------------------- start transmit
-----------------------------------------------------------------

 

            for (i=0;i<16;i++) scratch[i] = 'a';

            

            ioctl(QSMCM_QSCI1, QSCI_ENABLE_TX_WRAP, SCI_ENABLE); 

            ioctl(QSMCM_QSCI1, QSCI_WRITE_QUEUE_TX_SIZE, 16);

            

            /* read SR with TC set */

            while(!(ioctl(QSMCM_SCI1, SCI_GET_FLAGS, SCI_TX_COMPLETE))) {;}


            

 

              /* fill the whole buffer */  

              write(QSMCM_QSCI1, QUEUE_TOP_HALF, scratch, 16);

 

              /* Clear top half and bottom half flags QTHE/QBHE */

              ioctl(QSMCM_QSCI1, QSCI_CLEAR_QUEUE_FLAGS, QSCI_TX_TOP_HALF);

              ioctl(QSMCM_QSCI1, QSCI_CLEAR_QUEUE_FLAGS, QSCI_TX_BOT_HALF);

            

              /* Set queued enable flag in control register QTE */


              ioctl(QSMCM_QSCI1, QSCI_QUEUE_TX, SCI_ENABLE);

              /* Set QSCI transmit enable flag in control register TE */

              ioctl(QSMCM_SCI1, SCI_TRANSMITTER, SCI_ENABLE);

 

 

--------------------------------------------------------- ISR
----------------------------------------------------------------------------
---

 

  if (ioctl(QSMCM_QSCI1, QSCI_GET_QUEUE_FLAGS, QSCI_TX_BOT_HALF))

  {

      ioctl(QSMCM_QSCI1, QSCI_ENABLE_TX_WRAP, SCI_ENABLE); 
      ioctl(QSMCM_QSCI1, QSCI_WRITE_QUEUE_TX_SIZE, 16);

       /* read SR with TC set */
      while(!(ioctl(QSMCM_SCI1, SCI_GET_FLAGS, SCI_TX_COMPLETE))) {;}  

      for (i=0;i<14;i++) scratch[i] = 'c';
      scratch[14] = (u_char)13;
      scratch[15] = (u_char)10;
      write(QSMCM_QSCI1, QUEUE_TOP_HALF, scratch, 16);

      ioctl(QSMCM_QSCI1, QSCI_CLEAR_QUEUE_FLAGS, QSCI_TX_TOP_HALF);
      ioctl(QSMCM_QSCI1, QSCI_CLEAR_QUEUE_FLAGS, QSCI_TX_BOT_HALF);

      if (data[0]< 6)  /* stop after 5 interrupts */
      {
         ioctl(QSMCM_QSCI1, QSCI_QUEUE_TX, SCI_ENABLE);
         ioctl(QSMCM_SCI1, SCI_TRANSMITTER, SCI_ENABLE);
      }
      else
      {
         ioctl(QSMCM_QSCI1, QSCI_QUEUE_TX, SCI_DISABLE);
         ioctl(QSMCM_SCI1, SCI_TRANSMITTER, SCI_DISABLE);
      }
   }

 


-----Original Message-----
From: efi332-bounces at diy-efi.org [mailto:efi332-bounces at diy-efi.org] On
Behalf Of John Honnold
Sent: Wednesday, December 07, 2005 1:31 PM
To: efi332 at diy-efi.org
Subject: Re: [Efi332] Queued SCI transmit with interrupts on MPC555

David:

   What seems to be the problem?  I work for Freescale
with the MCUs, so I may be able to help.  Let me know
some specifics.

Regards,

John Honnold

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