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[SOLVED] Issue with 68K SOC example
10-21-2014, 10:48 PM (This post was last modified: 10-25-2014 08:43 AM by rpandion.)
Post: #1
[SOLVED] Issue with 68K SOC example
I tried the Pong demo when I received my board a couple of days ago and it worked like a charm.

Now, I'm willing to test the 68K SOC example but I can't make it work. I tried both the example on the homepage and the juggler demo from the forum and hit the same problem: the display is distorded and somewhat blinking (as if there was a sync issue). I tried on 2 different screens with no luck either.

Any ideas?
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10-22-2014, 10:00 AM (This post was last modified: 10-23-2014 12:24 AM by Fleasystems.)
Post: #2
RE: Issue with 68K SOC example
(10-21-2014 10:48 PM)rpandion Wrote:  I tried the Pong demo when I received my board a couple of days ago and it worked like a charm.

Now, I'm willing to test the 68K SOC example but I can't make it work. I tried both the example on the homepage and the juggler demo from the forum and hit the same problem: the display is distorded and somewhat blinking (as if there was a sync issue). I tried on 2 different screens with no luck either.

Any ideas?

Hello,

While the video output produced by the 68K SOC's VGA controller is not what I would call perfect (horizontal pixels are shifted two positions to the right with respect to the logical video buffer address etc) Neither myself nor others have seen any issues with the actual timing/flicker. That's not to say it is completely bug-free however (Note I am not even using the latest version of tobiflex's TG68 CPU!), just that I have not seen any real issues with it.

There is also a ZPU-based version of the same SoC for you to quickly check out if you like. Let me know if the ZPU example also yields the same video problem.

Just curious, but have you also tried the Next186 softcore with your flea? That has no known display issues that I am aware of. Thanks!

Regards, Valentin

Edited by Fleasystems. Reason: tidy up
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10-25-2014, 04:30 AM
Post: #3
RE: Issue with 68K SOC example
Hello,

Thanks for your response.

(10-22-2014 10:00 AM)Fleasystems Wrote:  There is also a ZPU-based version of the same SoC for you to quickly check out if you like. Let me know if the ZPU example also yields the same video problem.
I've tried the ZPU-based version with no more luck :-(

(10-22-2014 10:00 AM)Fleasystems Wrote:  Just curious, but have you also tried the Next186 softcore with your flea? That has no known display issues that I am aware of. Thanks!
I'm trying to make it work but I'm struggling loading the BIOS from the SD card even though I have followed the instructions (but used dmde as the disk editor instead of HxD as I get "access denied" errors when I try to apply the changes to the disk with HxD). The "BIOS not present..." sentence shows up correctly on the screen though. I'll try again and wil report success of failure.

Richard.
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10-25-2014, 08:42 AM
Post: #4
RE: Issue with 68K SOC example
Fixed! Fixed! Fixed!

Actually, I was using plain SD cards and not a SDHC ones. As soon as I switched to a SDHC card, all softcores worked flawlessly.

Thanks for your help!
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10-25-2014, 11:34 AM (This post was last modified: 10-25-2014 01:11 PM by Fleasystems.)
Post: #5
RE: [SOLVED] Issue with 68K SOC example
(10-25-2014 08:42 AM)rpandion Wrote:  Fixed! Fixed! Fixed!

Actually, I was using plain SD cards and not a SDHC ones. As soon as I switched to a SDHC card, all softcores worked flawlessly.

Thanks for your help!

Thanks for your update! Glad to hear you have found your problem! Smile

Looking at the 68K bootstrap assembly (and subsequently going blind because I'm an Intel guy Big Grin) I cannot see any definitive support for anything other than SDHC.

I have only ever used SDHC for both TG68 and ZPU as that is all I have available for my current projects.

About Next186 - I believe I mention that fact in the Next186 how-to guide (i.e. bundled with the Next186 example bit-file), in that Next186 will only work with SDHC cards as that is what is supported by it's Bootloader ROM..

This thread will now be closed. Thanks again!

Regards Valentin
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