Recommended Posts

Jack,

 

I tried the card I use for the acorn atom also for the atari 800 and it works just fine. I can load *.car and *.atr. So I think it is not my card that is the fault. I tried a Philips a Kingston and a sandisk card with my acorn atom. All the cards give a N/A sign in *HELP and *CAT.

I am monday free so I can get some measerements with my osciloscoop. You will here from me.

 

Goos.

Share this post


Link to post
Share on other sites

Foft,

 

Thanks for that info - very useful.

 

What's really weird in this case is it's failing very early on - at the CMD0 - and up to this point I can't see any difference between your flow chart, and what the Atom code is doing.

 

Can I ask what kind of speed the SD Clock would be running at in the Atari?

 

Dave

Share this post


Link to post
Share on other sites

I use this spi master hardware:

https://www.eewiki.net/display/LOGIC/Serial+Peripheral+Interface+%28SPI%29+Master+%28VHDL%29

56Mhz clk, clk_div is set to 2. So I think about 14MHz but To be honest I never double checked with my scope or la!

Edit: of course init runs slow before the speed is boosted. I use a divider of 128 for that.

Oh and worth checking the code matches the flow chart:) http://www.scrameta.net/atarixlfpga_svn/trunk/atari_800xl/firmware/sd_direct/

Share this post


Link to post
Share on other sites

Foft,

 

Thanks for those links.

 

Turns out we are both using the same code (even the comments are identical).

 

I'll do some diffs later, to see if there are any subtle variations. This just isn't making sense....

 

Dave

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now