Input to the timerclk on the MPC8280

[annamaya]

Hi again,

I was looking at the serial code for U-Boot and
noticed that in the version I have which is 1.1.1,
SMC's are using BRG 6 and BRG 7 and SCC's are using
BRG's 0 through 3. I am guesing that you fixed this in
a older version of U-Boot. I justed wanted you to know
that it looks like this has been fixed in the current
U-Boot code. Thanks for your help again.


--- Hans Schillstrom <hans.schillstrom at pwav.com>
wrote:

> Hi,
> I have the same problem on MPC8270,
> and solved it two parts in u-boot:
> - Setup you PC[26] to somtething else than TMCLK ex.
> g,p. I/O
>     then you an automatic selecttion of BRG1 as
> source.
>     
> - Write a proper value in BRGC1 and make shure that 
>     bit 16-17 is 0 for selection of CPM as clock
> source.
> 
> and then you have to "move around the brgs" in
> (2.6.10)
> drivers/serial/cpm_uart/cpm_uart_cpm2.c
> 
> I moved smc 1&2 to brg7 & 8
> scc1 to brg2 etc
> scc4 ext clk (48MHz for USB)
> 
> void smc1_lineif(struct uart_cpm_port *pinfo)
> {
> 	volatile iop_cpm2_t *io = &cpm2_immr->im_ioport;
> 
> 	/* SMC1 is only on port D */
> 	io->iop_ppard |= 0x00c00000;
> 	io->iop_pdird |= 0x00400000;
> 	io->iop_pdird &= ~0x00800000;
> 	io->iop_psord &= ~0x00c00000;
> #ifndef CONFIG_RCB8270
> 	/* Wire BRG1 to SMC1 */
> 	cpm2_immr->im_cpmux.cmx_smr &= 0x0f;
> 	pinfo->brg = 1;
> #else
>         /* Wire BRG7 to SMC1 */
>         cpm2_immr->im_cpmux.cmx_smr &= 0x0f;
>         cpm2_immr->im_cpmux.cmx_smr |= 0x10;  /* BRG
> 7 */
>         pinfo->brg = 7;
> #endif
> }
> 
> I guess you can do it in many ways ...
> 
> Any one that knows why SMC1 & SMC2 gets the same BRG
> as SCC1 & SCC2
> 
> Regards
> /Hans
>  
> On Wed, 2005-01-19 at 23:08, annamaya wrote:
> > I've asked this question on this forum before but
> it
> > did not get answered. I tried asking the same
> question
> > in the U-Boot forum with no results. So, I am
> going to
> > try this again.
> > 
> > According to section 4.1.2 on Page 4-4 in the
> MPC8280
> > User's Manual, one should be able to use a
> combination
> > of  external clocks on Port C pins 25, 26, 27 and
> 29,
> > the CPM cloak and BRG1 to generate a 32KHz or a
> 4MHz
> > clock. I am unable to find  any code in u-boot or
> any
> > other place that initializes any of these pins to
> be
> > external clocks. And as for BRG1, I believe it is
> > being used for the SMC clock.
> > 
> > I am unable to understand how this is done. Can we
> > have a timerclk input WITHOUT an external clock
> > signal? Can I just use the CPM clock to generate
> this?
> > How is this being done in U-Boot now?
> > 
> > Thanks much for your help. I really need an answer
> to
> > this. 
> > 
> > 
> > 		
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