SMC2

SMC2

[Grant Carter]

Hi

I have been looking at uart.c in the kernel and have come across
something that I cannot figure out. Perhaps I am just being stupid.
Perhaps someone can set me straight please.

The following code is taken fron uart.c and is used to set up either
both SMC2 and SMC1 pins or, in the #else, just set up SMC1's pins.

#if USE_SMC2
        cp->cp_pbpar |= 0x00000cc0;
        cp->cp_pbdir &= ~0x00000cc0;
        cp->cp_pbodr &= ~0x00000cc0;
#else
        /* This will only enable SMC1 if you want SMC2 for something
else.
        */
        cp->cp_pbpar |= 0x000000c0;
        cp->cp_pbdir &= ~0x000000c0;
        cp->cp_pbodr &= ~0x000000c0;
#endif

When I look at my manuals, I see no reference made to the bits 20 and 21
in pbpar, pbdir or pbodr. How does setting those bits enable the SMC2
pins? Those are located in Port A (PA8 and PA9)

I guess my point is why are the Port B registers being modified for SMC2
pins which are found in Port A?

Many thanks
Grant

--
Grant Carter                              gcarter@eng.uct.ac.za
Department of Electrical Engineering      University of Cape Town
Tel: +27 (0)21 650-3467                   Fax: +27 (0)21 650-3465
                     "Coffee not found - operator halted!"

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Re: SMC2

[Dan Malek]

Grant Carter wrote:

> When I look at my manuals, I see no reference made to the bits 20 and 21
> in pbpar, pbdir or pbodr. How does setting those bits enable the SMC2
> pins? Those are located in Port A (PA8 and PA9)
>
> I guess my point is why are the Port B registers being modified for SMC2
> pins which are found in Port A?

Oh oh......are you using an 823 or 850?  Sorry about this, you will
have to change the code.  Someday, I have to finish up a better UART
driver.  You are the first person I know that is trying to use this
as a UART.  SMC2 is the first thing to disappear when using the parts
for other data communication protocols or interfaces, so custom
software tends to assign these for other purposes.  I seldom see anything
but SMC1 used for a UART, so making the driver better hasn't been
high on the list......


	-- Dan

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Re: SMC2

[Wolfgang Denk]

In message <393E80D7.9918BBE1@embeddededge.com> you wrote:
>
> Oh oh......are you using an 823 or 850?  Sorry about this, you will
> have to change the code.  Someday, I have to finish up a better UART
> driver.  You are the first person I know that is trying to use this
> as a UART.  SMC2 is the first thing to disappear when using the parts

I'm doing that, too.

In fact, it's the default configuration for the TQM8xxL modules (all of them).

The reason for that is that TQ uses the serial connector not only for
SMC1, but also for RESET (on the RTS pin) and autoboot enable (on the
DTR pin). While this is handy when you know  about  it  and  use  the
right cable, it has confused enough of my customers to avoid using it
as a default :-(

> for other data communication protocols or interfaces, so custom
> software tends to assign these for other purposes.  I seldom see anything
> but SMC1 used for a UART, so making the driver better hasn't been
> high on the list......

Well, Dan, There are more things in heaven and earth, ..., Than are
dreamt of in your philosophy. ... :-)

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Delta: We never make the same mistake three times.  - David Letterman

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Re: SMC2

[Dan Malek]

Wolfgang Denk wrote:

> Well, Dan, There are more things in heaven and earth, ..., Than are
> dreamt of in your philosophy. ... :-)

Yeah....OK.


	-- Dan

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RE: SMC2

[Wohlgemuth, Jason]

Grant,

Look in your PowerQuicc 860 User's Manual on page 34-9,

Their is a table which show the proper pbpar,pbdir setting to enable smc2 (I
think).  I don't know how to explain the pbodr setting right off the top of
my head.  But it is in pages close to this one.

Hope that helps,
Jason

-----Original Message-----
From: owner-linuxppc-embedded@lists.linuxppc.org
[mailto:owner-linuxppc-embedded@lists.linuxppc.org]On Behalf Of Grant
Carter
Sent: Wednesday, June 07, 2000 8:35 AM
To: linuxppc-embedded
Subject: SMC2

I have been looking at uart.c in the kernel and have come across
something that I cannot figure out. Perhaps I am just being stupid.
Perhaps someone can set me straight please.

The following code is taken fron uart.c and is used to set up either
both SMC2 and SMC1 pins or, in the #else, just set up SMC1's pins.

#if USE_SMC2
        cp->cp_pbpar |= 0x00000cc0;
        cp->cp_pbdir &= ~0x00000cc0;
        cp->cp_pbodr &= ~0x00000cc0;
#else
        /* This will only enable SMC1 if you want SMC2 for something
else.
        */
        cp->cp_pbpar |= 0x000000c0;
        cp->cp_pbdir &= ~0x000000c0;
        cp->cp_pbodr &= ~0x000000c0;
#endif

When I look at my manuals, I see no reference made to the bits 20 and 21
in pbpar, pbdir or pbodr. How does setting those bits enable the SMC2
pins? Those are located in Port A (PA8 and PA9)

I guess my point is why are the Port B registers being modified for SMC2
pins which are found in Port A?

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Re: SMC2

[Grant Carter]

Hi

Sorry I forgot to mention that this was for an 823. I am told that those
bits are correct for the 860, as PB20/PB21 are SMRXD2/SMTXD2 of SMC2. I just
wasn;t sure how that code worked for the 823. The manual I am currently
using is the MPC823UM/D and have also looked at the preliminary manuals for
the 823e but with no further luck.

Regards
Grant

--
Grant Carter                              gcarter@eng.uct.ac.za
Department of Electrical Engineering      University of Cape Town
Tel: +27 (0)21 650-3467                   Fax: +27 (0)21 650-3465
                     "Coffee not found - operator halted!"

----- Original Message -----
From: "Wohlgemuth, Jason" <jason.wohlgemuth@marconi.com>
To: "'Grant Carter'" <gcarter@eng.uct.ac.za>; "'linuxppc-embedded'"
<linuxppc-embedded@lists.linuxppc.org>
Sent: Wednesday, June 07, 2000 4:19 PM
Subject: RE: SMC2


> Grant,
>
> Look in your PowerQuicc 860 User's Manual on page 34-9,
>
> Their is a table which show the proper pbpar,pbdir setting to enable smc2
(I
> think).  I don't know how to explain the pbodr setting right off the top
of
> my head.  But it is in pages close to this one.
>
> Hope that helps,
> Jason
>
> -----Original Message-----
> From: owner-linuxppc-embedded@lists.linuxppc.org
> [mailto:owner-linuxppc-embedded@lists.linuxppc.org]On Behalf Of Grant
> Carter
> Sent: Wednesday, June 07, 2000 8:35 AM
> To: linuxppc-embedded
> Subject: SMC2
>
>
>
> Hi
>
> I have been looking at uart.c in the kernel and have come across
> something that I cannot figure out. Perhaps I am just being stupid.
> Perhaps someone can set me straight please.
>
> The following code is taken fron uart.c and is used to set up either
> both SMC2 and SMC1 pins or, in the #else, just set up SMC1's pins.
>
> #if USE_SMC2
>         cp->cp_pbpar |= 0x00000cc0;
>         cp->cp_pbdir &= ~0x00000cc0;
>         cp->cp_pbodr &= ~0x00000cc0;
> #else
>         /* This will only enable SMC1 if you want SMC2 for something
> else.
>         */
>         cp->cp_pbpar |= 0x000000c0;
>         cp->cp_pbdir &= ~0x000000c0;
>         cp->cp_pbodr &= ~0x000000c0;
> #endif
>
> When I look at my manuals, I see no reference made to the bits 20 and 21
> in pbpar, pbdir or pbodr. How does setting those bits enable the SMC2
> pins? Those are located in Port A (PA8 and PA9)
>
> I guess my point is why are the Port B registers being modified for SMC2
> pins which are found in Port A?
>
> Many thanks
> Grant
>
> --
> Grant Carter                              gcarter@eng.uct.ac.za
> Department of Electrical Engineering      University of Cape Town
> Tel: +27 (0)21 650-3467                   Fax: +27 (0)21 650-3465
>                      "Coffee not found - operator halted!"
>
>


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Re: SMC2

[Dan Malek]

Grant Carter wrote:

> Sorry I forgot to mention that this was for an 823.

Ooops.  I guess I should read ahead......

To make SMC2 work on the 823/850 you need to set bits 8 and 9 in
port A papar, clear those bits in padir, and you probably want to
set bit 9 in paodr (it may not be necessary, but it is logically correct).
Everything else in the driver should be OK.


	-- Dan

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RE: SMC2

[Brown, David (dbrown03)]

Bright Star's ipEngine, using an 823, has SMC1 and SMC2 also.
When used with their pKernel, both serial ports are available.
When used with Linux, only SMC1 is available.
I noticed it, and thought it might be easy to fix, but
that's not important to me, since I only use the ipEngine for prototyping.
--
Dave Brown <dbrown03@harris.com>
Principal Engineer, Software
Harris Corporation RFCD

> -----Original Message-----
> From: Dan Malek [mailto:dan@netx4.com]
> Sent: Wednesday, June 07, 2000 1:05 PM
> To: Grant Carter
> Cc: linuxppc-embedded
> Subject: Re: SMC2
>
>
>
> Grant Carter wrote:
>
> > When I look at my manuals, I see no reference made to the
> bits 20 and 21
> > in pbpar, pbdir or pbodr. How does setting those bits
> enable the SMC2
> > pins? Those are located in Port A (PA8 and PA9)
> >
> > I guess my point is why are the Port B registers being
> modified for SMC2
> > pins which are found in Port A?
>
> Oh oh......are you using an 823 or 850?  Sorry about this, you will
> have to change the code.  Someday, I have to finish up a better UART
> driver.  You are the first person I know that is trying to use this
> as a UART.  SMC2 is the first thing to disappear when using the parts
> for other data communication protocols or interfaces, so custom
> software tends to assign these for other purposes.  I seldom
> see anything
> but SMC1 used for a UART, so making the driver better hasn't been
> high on the list......
>
>
> 	-- Dan
>

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/