Input to the timerclk on the MPC8280

[Hans Schillstrom]

Hi,

On Thu, 2005-01-20 at 16:47, annamaya wrote:
> Thanks a lot for the reply. I have some more questions
> on this. When and where in U-Boot do you set the value
> of BRGC1? Can I do this somewhere in board_init() or
> do I have to do it earlier, like in cpu_init? 
I think misc_init_f(), is a good idea
rememer to enable it with CONFIG_MISC_INIT_F

> And I
> will have to set the values in the DIV16 and CD to
> produce an output of 4Mhz or 32Khz. Is that correct?
> 
Yes

> BTW, how was this ever done on the MPC8260? I dont see
> any code in U-Boot for an 8260 board that does sothing
> similar?
> 
I havn't seen it before....

> --- 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 sure 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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> 
> 
> 
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