|
|
From drorex+yahoo@... Fri Sep 12 16:02:44 2008
Return-Path: <drorex@...>
Received: (qmail 58181 invoked from network); 12 Sep 2008 23:02:43 -0000
Received: from unknown (66.218.67.97)
by m45.grp.scd.yahoo.com with QMQP; 12 Sep 2008 23:02:43 -0000
Received: from unknown (HELO n13a.bullet.sp1.yahoo.com) (69.147.64.112)
by mta18.grp.scd.yahoo.com with SMTP; 12 Sep 2008 23:02:43 -0000
Received: from [69.147.65.149] by n13.bullet.sp1.yahoo.com with NNFMP; 12 Sep 2008 23:02:43 -0000
Received: from [66.218.66.81] by t9.bullet.mail.sp1.yahoo.com with NNFMP; 12 Sep 2008 23:02:43 -0000
X-Sender: drorex@...
X-Apparently-To: gbadev@yahoogroups.com
X-Received: (qmail 49776 invoked from network); 12 Sep 2008 23:01:04 -0000
X-Received: from unknown (66.218.67.96)
by m57.grp.scd.yahoo.com with QMQP; 12 Sep 2008 23:01:04 -0000
X-Received: from unknown (HELO yw-out-1718.google.com) (74.125.46.157)
by mta17.grp.scd.yahoo.com with SMTP; 12 Sep 2008 23:01:04 -0000
X-Received: by yw-out-1718.google.com with SMTP id 6so404695ywa.80
for <gbadev@yahoogroups.com>; Fri, 12 Sep 2008 16:01:03 -0700 (PDT)
X-Received: by 10.151.38.12 with SMTP id q12mr6858074ybj.198.1221260463599;
Fri, 12 Sep 2008 16:01:03 -0700 (PDT)
X-Received: by 10.151.8.8 with HTTP; Fri, 12 Sep 2008 16:01:03 -0700 (PDT)
Message-ID: <d3b404550809121601j79d834f2x606b74dde5fba4a7@...>
Date: Fri, 12 Sep 2008 16:01:03 -0700
To: gbadev@yahoogroups.com
In-Reply-To: <g9ucf5+cm5e@eGroups.com>
MIME-Version: 1.0
Content-Type: multipart/alternative;
boundary="----=_Part_52609_25976140.1221260463575"
References: <g9ucf5+cm5e@eGroups.com>
X-Originating-IP: 74.125.46.157
X-eGroups-Msg-Info: 1:12:0:0:0
X-eGroups-From: "David Rorex" <drorex@...>
From: "David Rorex" <drorex+yahoo@...>
Subject: Re: [gbadev] Question about sequential memory access
X-Yahoo-Group-Post: member; u=225506675; y=V8pKAPgC0ql_ULzDfTdvlKylxh2QfEyRF3mX3uK2S6EF
X-Yahoo-Profile: josath
X-Yahoo-Newman-Property: groups-system
X-eGroups-Approved-By: vbrunn3r <vbrunner_@...> via web; 12 Sep 2008 23:02:41 -0000
------=_Part_52609_25976140.1221260463575
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
Have you looked at this page? Has lots of info on it.
http://www.reinerziegler.de/GBA/gba.htm#How%20does%20the
Anyway, my understanding is that the high 8 bits of the address coming out
of the GBA are always valid, since they are not multiplexed. So you can have
counters on the whole 24 bits if you want, or just have counters for 16 bits
and read the other 8 bits from the address lines on every access, either
should work.
Perhaps you could give us some more detail on what exactly you are trying to
do? And you might want to look at the DS as well, it has a lot more power &
features, and still has the GBA cart interface.
-David R
On Sat, Sep 6, 2008 at 9:51 AM, dreamflighter78 <simnav@...> wrote:
> Hi to everybody,
>
> I'm new here but I'm studying how to "bend" GBA to use it for
> something different from gaming. I'm trying to understand how
> sequential memory access works: I readed that firstly a non sequential
> access is needed, lower 16 bits of address are put on AD0-AD15 and
> latched into a counter keeping /CS low while higher 8 bits of address
> are direcly put on A16-A23 then when /RD goes low, data out from flash
> and it is latched by GBA on /RD rising edge. The doubt is what happens
> in sequential access: /CS should remain low when /RD goes high, this
> will increment by one the counter containing the 16 bit lower part of
> address but what happens if previous readed address in non sequential
> way is for example 0x00ffff ? New address will be 0x000000 !? What's
> the mistake ? Pheraps counter have to latch and count all 24 bits ?
>
> Thank you.
> Regards,
> Simone Navari.
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>
------=_Part_52609_25976140.1221260463575
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
<div dir="ltr">Have you looked at this page? Has lots of info on it.<br><a href="http://www.reinerziegler.de/GBA/gba.htm#How%20does%20the">http://www.reinerziegler.de/GBA/gba.htm#How%20does%20the</a><br><br>Anyway, my understanding is that the high 8 bits of the address coming out of the GBA are always valid, since they are not multiplexed. So you can have counters on the whole 24 bits if you want, or just have counters for 16 bits and read the other 8 bits from the address lines on every access, either should work.<br>
<br>Perhaps you could give us some more detail on what exactly you are trying to do? And you might want to look at the DS as well, it has a lot more power & features, and still has the GBA cart interface.<br><br>-David R<br>
<br><div class="gmail_quote">On Sat, Sep 6, 2008 at 9:51 AM, dreamflighter78 <span dir="ltr"><<a href="mailto:simnav@...">simnav@...</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hi to everybody,<br>
<br>
I'm new here but I'm studying how to "bend" GBA to use it for<br>
something different from gaming. I'm trying to understand how<br>
sequential memory access works: I readed that firstly a non sequential<br>
access is needed, lower 16 bits of address are put on AD0-AD15 and<br>
latched into a counter keeping /CS low while higher 8 bits of address<br>
are direcly put on A16-A23 then when /RD goes low, data out from flash<br>
and it is latched by GBA on /RD rising edge. The doubt is what happens<br>
in sequential access: /CS should remain low when /RD goes high, this<br>
will increment by one the counter containing the 16 bit lower part of<br>
address but what happens if previous readed address in non sequential<br>
way is for example 0x00ffff ? New address will be 0x000000 !? What's<br>
the mistake ? Pheraps counter have to latch and count all 24 bits ?<br>
<br>
Thank you.<br>
Regards,<br>
Simone Navari.<br>
<br>
<br>
<br>
------------------------------------<br>
<br>
Yahoo! Groups Links<br>
<br>
<*> To visit your group on the web, go to:<br>
<a href="http://groups.yahoo.com/group/gbadev/" target="_blank">http://groups.yahoo.com/group/gbadev/</a><br>
<br>
<*> Your email settings:<br>
Individual Email | Traditional<br>
<br>
<*> To change settings online go to:<br>
<a href="http://groups.yahoo.com/group/gbadev/join" target="_blank">http://groups.yahoo.com/group/gbadev/join</a><br>
(Yahoo! ID required)<br>
<br>
<*> To change settings via email:<br>
mailto:<a href="mailto:gbadev-digest@yahoogroups.com">gbadev-digest@yahoogroups.com</a><br>
mailto:<a href="mailto:gbadev-fullfeatured@yahoogroups.com">gbadev-fullfeatured@yahoogroups.com</a><br>
<br>
<*> To unsubscribe from this group, send an email to:<br>
<a href="mailto:gbadev-unsubscribe@yahoogroups.com">gbadev-unsubscribe@yahoogroups.com</a><br>
<br>
<*> Your use of Yahoo! Groups is subject to:<br>
<a href="http://docs.yahoo.com/info/terms/" target="_blank">http://docs.yahoo.com/info/terms/</a><br>
<br>
</blockquote></div><br></div>
------=_Part_52609_25976140.1221260463575--
|
Fri Sep 12, 2008 11:01 pm
"David Rorex" <drorex+yahoo@...>
josath
 Online Now
 Send Email
|
|
Having problems with message search?
Fill out this form to ensure your group is one of the first to be migrated to the new message search system.
