PWM on the MPC850

Wolfgang Denk wd at denx.de
Thu Dec 12 00:43:15 EST 2002


In message <NDBBIHDFKLJKGJJGMFJOOEILCGAA.dmacarth at ufl.edu> you wrote:
>
> Does have any information regarding generating RC spec PWM signals using the
> MPC850
> that does not bog down the processor?  Also does anyone know how to expand

You can, to a certain degree, use the RISC timers to set up a  couple
of  PWM  channels  that run with zero CPU load (just some load on the
CPM). See the PWM driver (arch/ppc/8xx_io/pwm_8xx.c)  in  our  kernel
source tree.

But be warned: do NOT use any of the port B pins for I/O  in  such  a
setup. There is a race condition within all MPC8xx CPUs.

> the number
> of RS232 ports for the MPS850 from two to 2+.

Add one or more external  UARTs?  This  has  been  done  before  (for
example, we have a design with 2 x octal UARTs on a MPC8xx system).

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
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because people refuse to see it.           -- James Michener, "Space"

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