Applefritter Talk
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Your Dan ][ card may do that but mine doesn't. I just tried my card again without a Micro-SD card in it. It didn't continue the boot routine it just dropped into the monitor with the exact same thing on the screen that I posted earlier. CVT said to press the ESC key when booting the computer and it would ignore the Dan ][ card. That didn't work either. So, at least for me, the easiest thing to do is what I found and posted about after posting the comment about the problem. I have Apple II Desktop installed on the Micro-SD as BLKDEV01.PO. From there I just use the mouse I have hooked up to the IIe to scroll to Startup in the menu and select Slot 6. The computer then boots the 5.25 drive.
It may take a few seconds more on my part to get the program in the 5.25 to run but I'm perfectly happy with it. As I commented above at least this way I can run one of the 32mb images on the card or something in the 5.25 drives.
I may perhaps be stating the obvious or irrlelevant, but have you updated the card itself since obtaining it?
Yes, hitting ESC to skip booting and hitting SPACE to list the images of the microSD cards are two new features that were added only recently. You need to update both the EPROM chip firmware and the ATmega328 chip with the latest Arduino sketch.
So how do I do that? Hopefully it's something fairly simple.
All the instructions are posted within the first 3 pages of this topic.
Today I received mine and for some reason they don't work with the Dan ][ Controller. They are not defective, since both of them work on my laptop and on the ESP32 SoftCard that I am developing. However when I plug them in the Dan ][ Controller I cannot even see the files when I hit space.
It even doesn't work if I have the microSD card in slot 1 without an extender and just an empty extender in slot 2.
Sounds like it was picking up interference through the long leads when plugging the adapter. These adapter seem to be nothing else than SD slots with long extension leads. All signals, except the CS (chip select), are shared between the two slots - so, if there was an interference issue, it would easily affect both slots at the same time. The DAN II card uses simple resistor voltage dividers to convert the 5V TTL output of the ATMEGA to the 3.3V required for the SD cards (4k7 / 10k). So, these signals are not too strong and could be affected by interference. One could try to replace these resistors to make the signal a little stronger (like 470 Ohm / 1K).
Otherwise the adapter that Dan prepared would probably work better. It uses voltage dividers for the data signals on the adapter board, so the leads to the SD slot (after the divider) are still kept short. And, in fact, his external adapter already uses a 470 Ohm / 1KOhm voltage divider - so this design also uses stronger signals for the SD card. However, the CS and CS2 signals still uses 4K7 and 10K divider - and the 4k7 resistor is on the DAN 2 card (R27/R28). So this signal may still be affected by the same interference issue, like when using the AliExpress adapter.
dumb question from me: does the card work runtime as with my 6502 retro BBS system??
I completely wrapped one of the extenders with aluminum tape and grounded it, but it did not help, so if it’s due to interference it must be from one of the other lines in the ribbon. I will try with harder driving voltage divider resistors later.
I should have ordered more, so I can start cutting them with scissors and see exactly when the problem disappears, but I only got two and I rather like them, so I can’t do any destructive testing.
P.S. It turns out that these extenders have a 330 ohm internal pull up resistor between CLK and VDD. I am thinking of changing R9 from 470 to 47 ohms and R15 from 1K to 100 ohms.
Don't change to 47/100 ohms as that will probably draw too much current from the ATMEGA328P. I think you will have to remove the pullup.
It's unlikely to be interference that is causing the problems. The CS line uses 4k7/10k rather than 470R/1k dividers because the signal is relatively slow and doesn't require very fast transitions, unlike the CLK/MISO/MOSI lines.
I made an extender board that I haven't tried yet, but that would work as well. R27 and R28 should be populated with 4k7 resistors on the main board if this is to be used.
I didn't have 47/100 in my spares, but I changed R9/R15 to 80/160 ohms and it now works perfectly with both extenders. This should not draw more than 25 mA according to my calculations, which is still below the maximum of 40 mA for the 328P chip.
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