The GPIO read register reports the "pin state", which may not be the value you
wrote to the gpio, (if its shorted, etc)
-Curtis.
On August 21, 2005 05:06 pm, Kaiwan N Billimoria wrote:
> Hi All,
>
> Am attempting to write a user-space driver program to use the DIO header
> facility on the TS-7200.
> I get access via mmap() to the gpio base addr (0x80840000), then set
> (poke) the PxDDR register (where x is one of A-C, E-H) for output
> (setting some bit(s) high), then attempt to write (poke) the
> corresponding PxDR register. AFAIK that's the procedure to be followed
> according to the EP9301 User Manual. Am I right until here?
>
> Well, it seems that no matter what GPIO DDR register i'm writing to and
> what bit patter is being written, it's value (when peeked) is 0xff. ??
> For example, trying to use Port B, I write 0x04 to PBDDR, but on peeking
> it's value is 0xff. So, measuring w/ a voltmeter on the DIO header I can
> see that all relevant Port B lines are high.
> What I require is that my program can set the lines (DIO0 thru DIO7)
> selectively.
>
> Of course this is all a moot point if this is not the "right" way to do
> GPIO in the first place. Any inputs would be appreciated..
>
> (For those who want to see the source file i've currently written (and
> got stuck on), pl find it here:
> http://www.designergraphix.com/kaiwan/projects/gpio/TS7200-gpio.html ; ).
>
> Regards,
> Kaiwan.
>
>
>
>
>
>
>
> SPONSORED LINKS
> Linux os Hardware Arms
> Computer internet Computer security Computer hardware security
>
>
> YAHOO! GROUPS LINKS
>
>
> Visit your group "ts-7000" on the web.
>
> To unsubscribe from this group, send an email to:
>
>
> Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>
>
------------------------ Yahoo! Groups Sponsor --------------------~-->
<font face=arial size=-1><a
href="http://us.ard.yahoo.com/SIG=12htmne2c/M=362329.6886308.7839368.1510227/D=groups/S=1705005378:TM/Y=YAHOO/EXP=1124736108/A=2894321/R=0/SIG=11dvsfulr/*http://youthnoise.com/page.php?page_id=1992
">Fair play? Video games influencing politics. Click and talk back!</a>.</font>
--------------------------------------------------------------------~->
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|