Bought a new SDHC card for the M65

[Daniel England]

Heyas!

I thought I would post these questions here even though they are directed at Paul because I think that other people are going to want to know the answers.

So...

Paul, I bought a new 16GB SDHC micro SD Card today and I am trying to use it with the M65.

I thought I'd try to use it as it came.  The bitstream loads fine but the M65 says that it can't use it and drops me into the utilities menu.

Should I try to use the FDisk utility to fix setup the card or should I do it manually?  Just so we know, what are the settings the FDisk utility would attempt to apply?

I'm concerned that I would lose the bitstream if I used the FDisk utility and would probably prefer to set up the card myself and also so I know what the M65 requires in the future.

Its so much faster than my old card (and about 64 times the size - I was using a really old one) so I really want to use it.

Daniel.

[Paul Gardner-Stephen]

Hello,

FDISK will make a 2GB system partition, and the rest will be FAT32.  If you are loading the bitstream from SD card, you will need to copy it on again after.

Paul.

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[Daniel England]

Paul told me (he forgot to reply to the group) that the FDisk utility would make a 2GB M65 system partition and the remaining area would be created as a FAT32 partition.

Because I want the system partition and its the only way to get it, I need to use the FDisk utility.

However, the FDisk utility seems to be broken.  In the a bitstream built only yesterday, I get the following screen when I select it:

As you can see, I cannot FDisk and Format the card.

Is this something you'd like to me to look into, Paul?

Daniel.

[Daniel England]

I didn't use monitor_load to get into FDisk, I selected it from the boot menu.

Could it be that it needs the $D018 setting that you put in the config utility?

Daniel.

Paul said:

Hello,

I did see that at some point, but don't remember the specific reason. It could be you have used -c or -C wrong way around on monitor_load.

See what the serial monitor has to say about where it thinks it is with the CPU. Also, just try resetting and trying again.

[Paul Gardner-Stephen]

Not sure, check what D018 has, and try setting it to different sensible values, and see if that gets you a sensible looking display. I recall $14 and $21 being two candidate values.

Paul.

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[Daniel England]

Argh...  I tried to use m65dbg but I forget what the actual 24bit address is for the IO in 64 mode.

I checked the source code for fdisk and it needs the screen set at $8000 and the charset at $8800 so $D018 should be set to $12, after checking the C64PRG.

It seems that the following code to set $D018 in screen.c is incorrect, however:

  // Put screen memory somewhere (2KB required)

  // We are using $8000-$87FF for screen

  // Using custom charset @ $A000

  *(unsigned char *)0xD018U=

    (((CHARSET_ADDRESS-0x8000U)>>11)<<1)

    +(((SCREEN_ADDRESS-0x8000U)>>10)<<4);

SCREEN_ADDRESS is set to $8000 so it will attempt to load $D018 with $02 not $12.  And the comment is incorrect because CHARSET_ADDRESS is set to $8800.

Daniel.

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[Paul Gardner-Stephen]

Hello,

$02 is the correct value (and I confirm that it is set to that on FDISK here, which is displaying fine for me).  The comment is, yes, incorrect.

Paul.

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[Daniel England]

Oh yes..  I was looking at the wrong register value.  I've had a long day.

Perhaps it is that you aren't setting $DD02 to ensure that the bits are output?

I don't know..  I'd need to see what I can do in m65dbg but I don't know what the physical address is for the registers.  I know its been said before but I forget.

Daniel.