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Re: [PATCH] stm32 uart: use 16bit register access
- From: Nick Garnett <nickg at ecoscentric dot com>
- To: Spencer Oliver <spen at spen-soft dot co dot uk>
- Cc: ecos-patches at ecos dot sourceware dot org
- Date: 17 May 2010 12:10:15 +0100
- Subject: Re: [PATCH] stm32 uart: use 16bit register access
- References: <4BE012B0.70202@spen-soft.co.uk>
Spencer Oliver <spen@spen-soft.co.uk> writes:
> stm32 uart: use 16bit register access
>
> Access all uart register using 16bit access, as per the ST docs.
The ST docs I have, RM0008 version 11 from April 2010, show these
registers as 32 bits wide. The top 16 bits are alway marked as
reserved, so 16 bit accesses should work and the document says "The
peripheral registers can be accessed by half-words (16-bit) or words
(32-bit)." Nothing that requires 16 bit accesses. Given that ST have
left the 32 bit headroom, and that some of the registers are already
using all 16 low order bits, I think it would be a mistake to switch
to 16 bit accesses. Future versions might start using the higher order
bits, and we would just have to switch back.
Was there a specific reason you wanted to use 16 bit accesses rather
than 32 bit?
--
Nick Garnett eCos Kernel Architect
eCosCentric Limited http://www.eCosCentric.com The eCos experts
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