SCC character recognition/DMA

SCC character recognition/DMA

[Pergola, Michael]

All,

I have an Embedded Planet with a LITE_DW Motorola 823 PPC
using a HIOX interface board.

Has anyone attempted to utilize the character-recognition
feature of the SCC ports with any success?

Also, I have been researching the uart.c and related files but I
don't see if DMA is used to shuttle data to/from the serial
ports. Has that been attempted?

Regards,
     Michael Pergola
     Software Engineer
     Danfoss Air-Conditioning & Refrigeration Division
     7941 Corporate Blvd.
     Baltimore, MD  21236     (410) 931-8250 x4259


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Re: SCC character recognition/DMA

[Dan Malek]

"Pergola, Michael" wrote:

> Has anyone attempted to utilize the character-recognition
> feature of the SCC ports with any success?

Yes, it does work, just make sure you have an SCC to use (there
is only one on the 823, which is typically wired for Ethernet).

> ...... but I
> don't see if DMA is used to shuttle data to/from the serial
> ports. Has that been attempted?

The DMA must be used.  It is the only way the CPM moves data to/from
the devices.  There is no programmed I/O to 8xx peripherals except
the GPIO pins.


	-- Dan

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RE: SCC character recognition/DMA

[Pergola, Michael]

> -----Original Message-----
> From:	Dan Malek [SMTP:dan@mvista.com]
> Sent:	Tuesday, July 31, 2001 2:41 PM
> To:	Pergola, Michael
> Cc:	'linuxppc-embedded@lists.linuxppc.org'; Support (E-mail)
> Subject:	Re: SCC character recognition/DMA
>
> "Pergola, Michael" wrote:
>
> > Has anyone attempted to utilize the character-recognition
> > feature of the SCC ports with any success?
>
> Yes, it does work, just make sure you have an SCC to use (there
> is only one on the 823, which is typically wired for Ethernet).
	[Pergola, Michael]
	The 823e that comes with the Embedded Planet Dev Box
	has 3 SCCs but one is dedicated to USB while another is
	used for Ethernet. I guess my real question is, rather then
	re-invent the code, is there an implementation of the
	character recognition out there in GPL land?

	Michael Pergola

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Re: SCC character recognition/DMA

[Dan Malek]

"Pergola, Michael" wrote:

>         The 823e that comes with the Embedded Planet Dev Box
>         has 3 SCCs but one is dedicated to USB while another is
>         used for Ethernet.

Not exactly.  The USB controller is a USB controller.  It is
mapped into the address space of one SCC, and may use some of that
peripheral hardware, but it is not configurable as a SCC.
Since you have the 823e, yes SCC3 can be used.

> .... I guess my real question is, rather then
>         re-invent the code, is there an implementation of the
>         character recognition out there in GPL land?

I believe all the "character recognition" does is either map characters
or terminate buffer operations.  If the device is still used as a uart,
just modify the driver to initialize the characters you want (as it
stores defaults right now).  You can be a little more fancy and add an
ioctl() if you want.  If you want a custom driver that isn't a uart,
then you have to write a new driver.


	-- Dan

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