Accessing SD files using I/O

Stokedcat

Hi All,

My 1st post and I'm sure it won't be my last .

I have purchased the u-Oled 96 Prop board created my bmp and some dat files and stored them on an SD card......easy so far.

Now I want to access the the bmp's and or dat files to show the graphics when I change state of the 4 i/o pins on the u-Oled 96.

I have used the Rs232 spin files and the excellent Rs232 pc interface to call my files great works fantastic.

However I am really struggling to simplifiy it and utilise the SD commands without the RS232 interface and make it a simple stand alone device controlled only by the i/o pins etc.....I can expand the i/o later by using a shift register or something.

Any help would be appreciated ......this is my 1st project and I'm close but no cigar...my main problem is accessing the SD card using I/O.

Hope this is clear what I'm trying to achieve.

Thanks for any help you can give me.

mctrivia

there is an sd fat object in the obex.

!!usd.spin will toggle all the io lines in a few test paterns and check for an sd card on p0-p3.

don't have that screen but this may help.

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Stokedcat

Thanks I'll give it a try and let you know how I get on

Cheers

MagIO2

Nope ... it's not very clear what you want.

Is it that you want to show different pictures in case the I/O pins change?
0000 -> show pic 0
0001 -> show pic 1
... and so on ...

Or do you want it mor like the buttons on an MP3 player:
0001 -> start/stop looping through the pictures
0010 -> next picture
0100 -> previous picture
1000 -> ?

What's connected to the I/Os? Buttons? Another controller? Parallel interface of a PC?

In both cases you need to recognize a change in the I/Os, so you can start with a loop that scans the I/O pins for a change

oldval := INA[noparse][[/noparse] pin0 ... pin4 ]
repeat
  waitpne( pinmask, oldval ) ' this waits until at least one of the I/Os changed
  ' missing: debounce in case you have buttons attached
  
  oldval := INA[noparse][[/noparse] pin0 ... pin4 ] ' read the new state of I/O pins (which is then the old value for the next iteration)
  case oldval
     %0000:
        'donothing
     %0001:
        'startstop
     %0010:
        ' forward
     %0100:
        ' backward
   

Post Edited (MagIO2) : 6/10/2009 2:01:15 PM GMT

Stokedcat

Hi

Your right on both counts I suppose.

it's buttons changing state from 0 to vcc and calling images, but perhaps using the other other method of up/down etc might be better?

Thanks for the guidance on the I/O


Cheers