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 21 
 on: September 08, 2021, 05:59:34 pm 
Started by Lisa2 - Last post by stepleton
Thanks James! Looks like I might need to find some different 2/10s for testing besides my own. About the only thing I can think of that might be different is that I'm not using any adaptor cable between my own device and the Widget cable, which I plug straight into the 26-pin header at the back of the Aphid board.

It's been about three years since I designed the Aphid board. It's possible that trying to use fancy all-in-one automatic bidirectional level adaptor ICs for the data and signaling lines was just too clever by half. (ProFile emulation was only meant to be one application for Aphid --- I wanted to have the board be useful for other things too, like GPIB. But I've never tried any other use.)

I think there are bidirectional level shifter ICs that require you to toggle the data direction with a pin; alternatively, you could do what the ProFile did and have two tri-state buffers, one for in and one for out. The R/~W line picks the active one directly, if I recall correctly. I suspect either would be more dependable. In the meantime, I wish I knew why my 2/10 was more tolerant than other folks' machines.

 22 
 on: September 08, 2021, 05:25:07 pm 
Started by Lisa2 - Last post by jamesdenton
It's worth saying that when James Denton was working on preparing this product derived from Cameo/Aphid, he needed to make some tweaks to get it working on the internal connector. Note the presence of Rev. A and Rev. B options on his page. I'm not sure how his Rev. B is made, but I know he was investigating a simpler replacement for the TXS0801 bidirectional level adaptor chips that I use in my design, which I think is a pretty good idea. James was planning to share his designs and may have already done it somewhere.

Thanks for the nudge - I've push the schematics, board, and related BOM to my forked repo here.

FWIW, the Rev A board uses the same components found in Tom's design and uses TXS0108s and 100ohm resistors (where necessary). Works well with Lisa 2/5 and Apple ///. Been a while since I tested with a parallel card. I was not able to get it to work reliably with my 2/10 using the internal cable. The same can be said for the original cameo/aphid I built.

Which brings me to Rev B - I used many BSS138s in place of the (2) TXS0108s. This has shown to work really well on the 2/10, along with the 2/5 and Apple ///. However, I have found the PocketBeagle's themselves to be a little more flaky with this board. Some work great 100% of the time, others are a bit more temperamental and I see checksum errors and various oddities.

 23 
 on: September 08, 2021, 04:04:40 pm 
Started by Lisa2 - Last post by stepleton
I remembered that thing about the faster clock on the parallel card; how that affects I/O with the Lisa I'm not sure. But if @Lisa2, you're willing to try your X/ProFile on the parallel port, that would be an excellent test of the difference.

I'm girding myself for the news that Cameo/Aphid really is slower! I never have tried to optimise it for speed, and there's a fair amount you could do to make it go faster. (Ditching python for C might be a start.) But I'm betting that most Lisa applications aren't really disk I/O bound. The main thing I'm worried about is compatibility, so that bit about it not working internally is what grabs my attention. Do you have the inline 100-ohm terminating resistors fitted? (I'm guessing you do.) These are what enables Widget replacement for me, but I haven't had more 2/10s to try it out on besides my own.

It's worth saying that when James Denton was working on preparing this product derived from Cameo/Aphid, he needed to make some tweaks to get it working on the internal connector. Note the presence of Rev. A and Rev. B options on his page. I'm not sure how his Rev. B is made, but I know he was investigating a simpler replacement for the TXS0801 bidirectional level adaptor chips that I use in my design, which I think is a pretty good idea. James was planning to share his designs and may have already done it somewhere.

 24 
 on: September 08, 2021, 03:52:34 pm 
Started by Lisa2 - Last post by Lisa2
This would seem to indicate that the Dual Parallel card is more than twice as fast as the internal port.  I am not sure this is case.  The Dual Parallel card manual also states the card has a "625K bytes/second maximum data transfer rate", I can't find this spec for the internal port right now.

I can test the same X/Profile on the Dual Parallel card and see if it's any faster... ;)

Rick

 25 
 on: September 08, 2021, 02:38:24 pm 
Started by Lisa2 - Last post by blusnowkitty
It would be nice to compare two drives on the same port; it's possible that the internal port and the expansion card could have different rates.

For what it's worth, I found this in the Parallel Card manual trying to debug my homemade DMP cable:

Quote
1. Timing. The Lisa parallel connector is driven by a 500 kHz clock. The Parallel Interface Card supports a faster clock operating at 1.25 M Hz. This affects software using 6522A internal timers.

https://generalphiles.com/files/Apple/Lisa/Parallel%20Interface%20Card.pdf
Page 14, or PDF page 21

 26 
 on: September 08, 2021, 02:08:47 pm 
Started by Lisa2 - Last post by Lisa2
A couple more quick notes on this:

1. I was using using the latest build of the Aphid software from this summer.

2. I think the SD card used in the Aphid is a class 10 ( I will confirm this later ).

3. The CF card in the X/Profile rated at 80x speed ( 80 x 150 kB = 12,000 kB or 12Mb ?? )

4. I did try connecting the Aphid to the internal port on the 2/10 without success so far ( I do have the correct cable for this ), but I can try the test again using both connected the dual par port card ( or to the same exact port if you want ).

5. I can also run the same test on a real profile or a widget if you want, I have both working available. 

Rick

 27 
 on: September 08, 2021, 01:45:00 pm 
Started by Lisa2 - Last post by stepleton
Wow, cool! Maybe I shouldn't write hard drive emulators in Python :-)

It would be nice to compare two drives on the same port; it's possible that the internal port and the expansion card could have different rates. Another factor might be the SD card in use inside the Aphid (as well as the media in the other devices). Most SD cards will be plenty quick, but the speed difference between an older Class 4 device and a Class 10 or better will likely be substantial in Cameo/Aphid.

One slightly obnoxious quirk of the internal I/O mechanisms that Cameo/Aphid uses is that data has to be passed around in 512-byte blocks. As a ProFile drive block is 532 bytes, you need two of these transfer operations to access a single block. If you wanted to, you could write these blocks directly to shared memory inside the PocketBeagle, but I chose the path of purity...

I wonder how a real drive would do!

 28 
 on: September 08, 2021, 11:30:09 am 
Started by Lisa2 - Last post by Lisa2
So I finally was able to put together a Cameo/Aphid device to play with. I was interested in the performance of the Cameo/Aphid vs. the X/Profile.  My test setup is a 2/10 running MW+II with an X/Profile in place of the Widget,  the Cameo/Aphid connected to a dual parallel port card, and a PCMCIA flash drive connected to a Sun SCSI card.  To test the performance of the drives I used an old HD benchmarking program from LaCie named TimeDrive.  This program does non-destructive testing using the driver ( not direct SCSI calls) so it's a good fit for these parallel port drives.  A made a quick video of the testing ( that my cat photo-bombed ), it's boring, shaky, and about 5 min. long, but for those who may be interested here is the link:

https://youtu.be/pDfxcUbvBc0

The test is not scientific, but the results were interesting.

Rick

 29 
 on: September 07, 2021, 08:11:23 pm 
Started by blusnowkitty - Last post by blusnowkitty
You might want to replace the foam "bumpers" on the edges of the mechanism. I used self-stick window gasket for mine. On the Canon the printer recalibrates often by moving the head left as far as it will go.

So does the 3852 I believe.

So I built myself a DMP cable according to the pinout above, and no dice. I'm seeing the same failure method that Tom did back in LisaList1 where the Lisa takes several minutes to error out on printing. Verified that everything is where it should be with a multimeter and nothing. I may try moving 16->10 to 16->11 and see if that does anything - can't imagine it would given the results in LisaList1, though...

ETA: Switched the pins. With the pins switched, the Lisa instantly says that the printer is not connected.

 30 
 on: September 07, 2021, 08:14:25 am 
Started by blusnowkitty - Last post by compu_85
That looks really good! The IBM font looks a bit nicer than the Canon one.

You might want to replace the foam "bumpers" on the edges of the mechanism. I used self-stick window gasket for mine. On the Canon the printer recalibrates often by moving the head left as far as it will go.

-J

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