[ECOS] Altera EPXA1 Excalibur: changing the clock output of PLL1
Stephan Bourduas
stephan@macs.ece.mcgill.ca
Tue Jun 22 03:59:00 GMT 2004
I'm trying to get dynamically reconfigure PLL1 on my EPXA1 board via the
procedure outlined in an177.pdf from the altera website. When I change the
clock output of PLL1, my serial output doesn't work anymore, but when I
change back to the default value, the serial port works propely.
I think that I somehow have to re-initialize the serial port to use the new
clock speed. Does anyone know how to do this?
Stephan
PS: below is a related email I found searching the lists:
> ecos-discuss Digest of: thread.27071
>
>
> Excalibur AHB1 clock change
> 27071 by: "J Jordaan" <jjordaan@sun.ac.za>
>
> From:
> "J Jordaan" <jjordaan@sun.ac.za>
>
>
> To:
> <ecos-discuss@sources.redhat.com>
>
>
> Date:
> 21/05/04 07:34 am
>
> Hi All
>
> I've been trying to change the AHB1 clock of the Altera Excalibur Epxa1
> board without any success. According to the datasheets you can change it in
> a user application by first bypassing the PLL1. You do this by setting the
> BP1 bit in the CLK_DERIVE register. I do this with the following commands :
>
>
>
> cyg_uint32 reg;
>
> HAL_READ_UINT32(EPXA1_CLK_BASE + _CLK_DERIVE, reg);
> reg |= 0x1000;
> HAL_WRITE_UINT32(EPXA1_CLK_BASE + _CLK_DERIVE, reg);
>
>
>
> The moment I do this the whole system just hangs. When a bypass the PLL2
> with the same commands, it works without a problem.
>
> Does anybody know what the problem could be or what I'm doing wrong?
>
> Thanks
> Jacques
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