Minimig not showing kickstart - help!

[wolfchild]

I have today jumped the hurdle of programming the PIC on my newly self assembled Minimig. 8-)  

It wasn't easy considering that I was so impatient to get it going that I built the programmer myself (RCD prog), only to find that it wouldn't work with the Minimig's PIC.  I finally hacked and it let me program the darned PIC.

Now I have yet another problem.  Upon power up, the Minimig seems to pass the RAM test (screen flashes green, red then blue) and then it starts loading kickstart (different colour screens with 'decrunching' flicker every now and then).  It then stops at showing a blue screen, and that's it.

The OSD works, and I can insert floppies, but nothing else happens.  I did not even get the kickstart screen.  

I was using a 32MB Panasonic SD card and KS2.04.  I'll try tomorrow same card with KS1.3.  I'll also give it a try with a 2GB SanDisk and KS1.3.

Has anyone been through this problem? Any hints about what's happening? I'm using the latest release from Dennis and no PIC bootloader.

Cheers!
Edwin

[wolfchild]

@Namek - Thanks for the tip.

I just tried the 2GB SanDisk.  Still the same problem. :-?

Last activity that happens is that the NumLock LED on the keyboard turns off.

I'll give the sources a look to see what might be happening.

[wolfchild]

Hi,

I encountered that problem too.  The firmware from Dennis does not set the config words, so I set them manually by copying those from the bootloader.

Which hex file did you use for the bootloader?  I went to the author's site and downloaded the latest TinyPic distro (version 1.97).  There is one for PIC18F252 and I programmed that.  It did not work for me however, so after a day's worth of trials, I gave up and flashed the Minimig firmware directly, and put the config word manually.

Currently I am programming using WinPic and a modified RCD programmer.  I should be receiving my PICKit2 clone shortly, but in the meantime I can't wait to get my Minimig up and running!

[wolfchild]

@ braindead
Thanks for your info!  You helped me a lot!  I used the bootloader you mentioned and it worked flawlessly.  I had to change serial cable too (must be null modem).

@boing4000
Following your post mentioning the reset, I put a logic probe on the 68k reset pin and in fact it goes LOW just after it completes flashing colours.  This also happens when I press ctrl+alt+alt.  So it seems that the 68k bootcode is working fine, and so is the core.

What I noticed is that the 68k and RAM buses are active during loading of the kickstart, but then go completely idle after the reset.  The only activity remaining is the CPU_CLK signal (68k pin 6).

I'm using a 512k KS1.3 and tried FPGA cores from Dennis and Yaqube.  If I don't get it running by end of week I'm going to shelf it until I have time to write a kickstart replacement that runs some extensive RAM tests.

I suspect there is some broken track somewhere which I can't see...

[wolfchild]

Thanks for your help guys!

I made another step forward.  I found that an address pin (A14) on one of the RAM chips was not soldered properly. (Shame on me, as I used to make SMD protoypes for a living up to 6 months ago!)

After fixing it, I have now a black screen, and activity on the RAM and CPU buses.  

The kickstart I am using works with UAE, so I still have some more hardware issues to look into.  I suspect a faulty RAM...

Unfortunately, the RAM test as provided by Dennis is not flawless and it will not detect problems on address lines.  Currently, on a faulty system it will write data to a wrong address and read it back from the same wrong address.  Only data line problems will be detected...

I found a better algorithm, from memtest86 tech info and if I do have time, I'll write my first ever 68k asm program which will be an extensive RAM test

I'll keep you guys posted.

Cheers!
Edwin