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Re: New Board Development - SBC6120-RBC Edition [message #5237 is a reply to message #5236] Sat, 29 September 2018 14:37 Go to previous messageGo to next message
boss is currently offline  boss
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For me as well.
Re: New Board Development - SBC6120-RBC Edition [message #5246 is a reply to message #5237] Sun, 30 September 2018 10:49 Go to previous messageGo to next message
Andrew B is currently offline  Andrew B
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I started a new thread on a simple Arduino checker to see if a chip is actually an HD1-6120:
https://www.retrobrewcomputers.org/forum/index.php?t=msg& ;th=328&start=0&
Re: New Board Development - SBC6120-RBC Edition [message #5308 is a reply to message #5246] Wed, 10 October 2018 14:22 Go to previous messageGo to next message
gkaufman is currently offline  gkaufman
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Picked up 2 more HD-6120's from UTSOURCE. They were listed as D1-6120-9C
https://www.utsource.net/itm/p/1887077.html

They appear old (some oxidation on pins, minor chips in ceramic) but original and both work perfectly.

$14.19 each, and they list 75653 in stock!!!

- Gary
Re: New Board Development - SBC6120-RBC Edition [message #5313 is a reply to message #4011] Thu, 11 October 2018 14:44 Go to previous messageGo to next message
scruss is currently offline  scruss
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will wrote on Tue, 26 December 2017 13:58
...
I measured the power consumption of my SBC6120, including IDE to CF adapter and CF card, as about 200mA. USB can easily deliver this.


Thanks for this. I may have to try it, as my recently-built SBC6120-RBC Edition successfully goes through POST but doesn't get to kick anything out the serial port. I suspect I may have fouled up the cabling. Or not found a terminal under Linux that can talk 7M1. 9-pin serial null-modems are much rarer beast these days than when the original SBC6120 came out.

One caveat about using FTDIs and the like is that - while USB can deliver 200 mA and beyond - they often negotiate to limit themselves to 100 mA. There's a milliamp rating (sometimes confusingly called "Max Power") in the USB parameters that shows you their current limit. SparkFun has a "Beefy" USB serial adapter that can deliver quite a bit more power, but is a lot more expensive.


> Does anyone know what each of the pins on the 6502 CPU chip in the Apple II Plus does?
They all plug into the socket on the motherboard to keep the chip from drifting away. - c.s.a2 FAQ of yore
Re: New Board Development - SBC6120-RBC Edition [message #5314 is a reply to message #5313] Thu, 11 October 2018 15:40 Go to previous messageGo to next message
tingo is currently offline  tingo
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FWIW, I found that simply doing 'screen /dev/ttyUSB0 9600' (or whatever your usb serial port is called) works. Of course, this was after I had spent some time trying to get usb-to-ttl adapters working (blush)...

Torfinn
Re: New Board Development - SBC6120-RBC Edition [message #5315 is a reply to message #5314] Thu, 11 October 2018 20:40 Go to previous messageGo to next message
scruss is currently offline  scruss
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Aha! The null modem cable I bought turned out to be straight-through. On rectifying, the console message came through. Yeah! Another successful SBC6120-RBC is built!

> Does anyone know what each of the pins on the 6502 CPU chip in the Apple II Plus does?
They all plug into the socket on the motherboard to keep the chip from drifting away. - c.s.a2 FAQ of yore
Re: New Board Development - SBC6120-RBC Edition [message #5320 is a reply to message #5315] Sat, 13 October 2018 12:50 Go to previous messageGo to next message
scruss is currently offline  scruss
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... though I shouldn't be too happy as I'm yet to get the thing to boot successfully.

I typically get the monitor prompt, but (B) isn't accepted:


SBC6120 ROM Monitor V320 Checksum 3752 6072 3515 09-APR-10 21:15:39
Copyright (C) 1983-2010 by Spare Time Gizmos. All rights reserved.

NVR: Not detected
IDE: 489MB - LEXAR ATA FLASH
IOB: Not detected

>BBBBBBBBB

This is just from pressing B once.

I did get a card to boot once, but unfortunately my serial params were wrong and all I got was noise

Are there any hints for troubleshooting booting, please?


> Does anyone know what each of the pins on the 6502 CPU chip in the Apple II Plus does?
They all plug into the socket on the motherboard to keep the chip from drifting away. - c.s.a2 FAQ of yore
Re: New Board Development - SBC6120-RBC Edition [message #5321 is a reply to message #5320] Sat, 13 October 2018 12:57 Go to previous messageGo to next message
Andrew B is currently offline  Andrew B
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Seems like you might still have some kind of a serial problem?

If you boot without the flash card attached, and type 'h <enter>' at the prompt, do you get the monitor ROM help?

Can you dump RAM, 'e 0000-1000 <enter>'
Re: New Board Development - SBC6120-RBC Edition [message #5322 is a reply to message #5321] Sat, 13 October 2018 14:40 Go to previous messageGo to next message
will is currently offline  will
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I had a problem with keys repeating - they would just repeat until the monitor's input buffer was full. It turned out that the GAL at U11 was not programmed correctly (or it was a faulty chip). I swapped in a newly programmed replacement GAL at U11 and the issue went away.
Re: New Board Development - SBC6120-RBC Edition [message #5323 is a reply to message #5322] Sat, 13 October 2018 15:03 Go to previous messageGo to next message
Andrew B is currently offline  Andrew B
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These GALs came from one of my wait list kits, so they were tested to boot & run Adventure off a CF card before being sent out. Not that there couldn't be a problem, but it would be the first I'd heard of with any of the kits or partial kits that I've sent out.

I have found that some of my CF cards are sensitive to the duration of the reset pulse and holding down the reset button for longer makes them come up. But I'd definitely recommend testing without the CF card first to make sure the monitor is running properly. (The monitor is pretty smart, when you ask for help for instance it only shows the IDE commands if there is an IDE drive detected!Wink

Re: New Board Development - SBC6120-RBC Edition [message #5324 is a reply to message #5323] Sun, 14 October 2018 01:34 Go to previous messageGo to next message
Simmo is currently offline  Simmo
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Yeah, I picked up a D1-6120-9C ($AUD17) and a HD3-6402R-9 ($AUD4.50) from UT Source which look OK. Hopefully they work. Yet to get myself a PCB, which I'll get shortly from Andrew B, and test these chips. Looking forward to a PDP adventure game myself.

Andrew B, let us know through the boardinventory page what you have left available for the SBC6120-RBC.

Thanks,
Simmo
Re: New Board Development - SBC6120-RBC Edition [message #5325 is a reply to message #5324] Sun, 14 October 2018 15:07 Go to previous messageGo to next message
Andrew B is currently offline  Andrew B
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So - there have been a few people who have been waiting a long while for 'wait list' stuff. Apologies to the people who have patiently waited. I hate to take any $$ unless I know I can ship promptly, so it's been slow going since I made the giant bath of 65 original kits. I'm ordering some GALs + EEPROMs to get caught up along with more PCBs. I have a few tested 6120s left but based on the wait list I have, I believe that they are all likely spoken for at this point. If I get through the list and any are left, I'll post back here.

The mis-numbered D1-6120 from UTSource seems like a good option right now.

[Updated on: Sun, 14 October 2018 15:07]

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Re: New Board Development - SBC6120-RBC Edition [message #5327 is a reply to message #5321] Mon, 15 October 2018 09:48 Go to previous messageGo to next message
scruss is currently offline  scruss
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Andrew B wrote on Sat, 13 October 2018 15:57
Seems like you might still have some kind of a serial problem?

If you boot without the flash card attached, and type 'h <enter>' at the prompt, do you get the monitor ROM help?

Can you dump RAM, 'e 0000-1000 <enter>'

Can't seem to do either. Entering 'H<cr><lf>' at the prompt usually returns a <lf>. This last time I've tried it, all three POST lights lit up and it seems to have hung.

(I'd be happy to start another thread about this, as my serial issues must be tedious for other readers.Wink

What I've tried/tested:
  • two different null modem cables
  • two different serial adapters
  • continuity between 6402 and MAX232: good
  • continuity between MAX232 and serial out: good
  • capacitors on MAX232 are all good
  • Replacing the MAX232 with a socket and USB serial adapter resulted in all three POST bits lit and no useful function
  • reset button often doesn't work, even if held for a long time and no CF2IDE adapter present. Usually resets to just power LED and no POST
  • both oscillators doing their job (or there would be no coherent monitor message)
  • no obvious bent pins or shorts in the dual-wipe sockets
  • I have been more careful with ESD precautions with this build than any other, given the dire warnings in the manual
  • The board was less compatible with my lead-free + no-clean flux soldering setup than I'd hoped
  • (smallest CF I current have is 512 MB, and written using Etcher; I'm getting smallest cards I could find by mail this week)
Guess I'll have to trace every line and see if something's not connected.


> Does anyone know what each of the pins on the 6502 CPU chip in the Apple II Plus does?
They all plug into the socket on the motherboard to keep the chip from drifting away. - c.s.a2 FAQ of yore
Re: New Board Development - SBC6120-RBC Edition [message #5336 is a reply to message #5327] Mon, 15 October 2018 20:02 Go to previous messageGo to next message
Andrew B is currently offline  Andrew B
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It sounds like you're getting to the end of all of the logical things to do.

Did you happen to substitute any of the 7400 series logic with a different series compared to what is in the BOM? We had strange intermittent issues with some 74ACT (I think?) chips on the Rev 0.99 board, but I went to thicker power & GND traces + 2 Oz copper on the Rev 1.xx boards and that seemed to resolve that issue, even the previously problematic chips worked fine.

Where did you source the rest of the chips for the build?

I don't mind if we stay in this thread or split it off, totally up to you.

[Updated on: Mon, 15 October 2018 20:03]

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Re: New Board Development - SBC6120-RBC Edition [message #5343 is a reply to message #5336] Wed, 17 October 2018 05:37 Go to previous messageGo to next message
scruss is currently offline  scruss
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All my logic chips are TI SN74HC... types, bought new from Digikey using your BOM generator, like all the other chips. I did find one dry joint on the low EEPROM, but fixing that made no difference. I may try the simple expedient of taking all the chips out and re-socketing them.

After that, I guess I'll have to test the logic chips one by one.


> Does anyone know what each of the pins on the 6502 CPU chip in the Apple II Plus does?
They all plug into the socket on the motherboard to keep the chip from drifting away. - c.s.a2 FAQ of yore
Re: New Board Development - SBC6120-RBC Edition [message #5375 is a reply to message #5343] Sat, 20 October 2018 20:41 Go to previous messageGo to next message
scruss is currently offline  scruss
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Reseated the chips ... and I don't even get POST any more ☹
Is there a way to get a nice connection table (basically a text version of the schematic, showing U1 P1 going to ___, U1 P2 going to ___, etc) from kicad? The schematics would be so much page flipping.


> Does anyone know what each of the pins on the 6502 CPU chip in the Apple II Plus does?
They all plug into the socket on the motherboard to keep the chip from drifting away. - c.s.a2 FAQ of yore
Re: New Board Development - SBC6120-RBC Edition [message #5376 is a reply to message #5375] Sat, 20 October 2018 20:52 Go to previous messageGo to next message
Andrew B is currently offline  Andrew B
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There should be a text file of the netlist in the .zip with the Gerber & KiCAD files. Take a look at SBC6120-RBC.net, in the bottom of the file all of the nets are listed.

If you want to post or send some pictures of the board, I'll take a look to see if there is anything amiss.
Re: New Board Development - SBC6120-RBC Edition [message #5388 is a reply to message #5376] Mon, 22 October 2018 15:00 Go to previous messageGo to next message
scruss is currently offline  scruss
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Thanks, Andrew. I managed to generate a sorted by component netlist using kinparse - https://github.com/xesscorp/kinparse .

Photos are here:

I fear I may have burnt off a couple of pads, so as long as there aren't too many I might be able to use patch wires. If not, I may have to come back to you for a new board.


> Does anyone know what each of the pins on the 6502 CPU chip in the Apple II Plus does?
They all plug into the socket on the motherboard to keep the chip from drifting away. - c.s.a2 FAQ of yore
Re: New Board Development - SBC6120-RBC Edition [message #7515 is a reply to message #5388] Mon, 13 April 2020 18:51 Go to previous messageGo to next message
scruss is currently offline  scruss
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Wheee! I finally got this rebuilt and tested: thanks for sending those boards, Andrew!

I'm still getting no keyboard response at the monitor:

SBC6120 ROM Monitor V320 Checksum 3752 6072 3515 09-APR-10 21:15:39
Copyright (C) 1983-2010 by Spare Time Gizmos.  All rights reserved.

NVR: Not detected
IDE: Not detected
IOB: Not detected

>H

But at lest the thing's not fried due to my terrible soldering last time!


> Does anyone know what each of the pins on the 6502 CPU chip in the Apple II Plus does?
They all plug into the socket on the motherboard to keep the chip from drifting away. - c.s.a2 FAQ of yore
Re: New Board Development - SBC6120-RBC Edition [message #7518 is a reply to message #7515] Tue, 14 April 2020 03:14 Go to previous messageGo to next message
will is currently offline  will
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Check hardware (RTS/CTS or DSR/DTR) flow control is disabled on your serial terminal (otherwise it may not transmit).

Pin 19 (DR) on the UART (U16) should go high when there is a character received and waiting for the PDP-8 to read out, and stay high until pin 18 (/DRR) on the same chip goes low.

These signals are both connected to IOT2 (U11) so check this chip is correctly programmed if the DR signal is apparently being ignored or /DRR is not being generated.
Re: New Board Development - SBC6120-RBC Edition [message #7520 is a reply to message #7518] Tue, 14 April 2020 06:06 Go to previous messageGo to next message
gkaufman is currently offline  gkaufman
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Not to suggest the most simple possiblility, but are you using 9600 baud, 7 bits, mark parity and 1 stop bit?

- Gary
Re: New Board Development - SBC6120-RBC Edition [message #7525 is a reply to message #7520] Tue, 14 April 2020 16:09 Go to previous messageGo to next message
scruss is currently offline  scruss
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Thanks! Caught the problem on the first elimination: the USB-Serial null-modem combo was wired wrongly. Swapping it for the one on my Zeta2 made it happy.

> Does anyone know what each of the pins on the 6502 CPU chip in the Apple II Plus does?
They all plug into the socket on the motherboard to keep the chip from drifting away. - c.s.a2 FAQ of yore

[Updated on: Tue, 14 April 2020 16:17]

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Re: New Board Development - SBC6120-RBC Edition [message #7980 is a reply to message #7525] Tue, 22 September 2020 14:17 Go to previous messageGo to next message
kb811 is currently offline  kb811
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I have just built two RBC versions of the SBC6120 and am pleased to report that they appear to work fine at both 5 and 8 MHz (for example: booting into OS/8 and running adventure).

The only problem I had eventually turned out to be the Microchip ATF22V10C[QZ] devices and the TL866II Plus programmer I used to program them - the SBC6120 would start up, but there were various random behaviour issues and it wouldn't boot into OS/8. Initially I thought it might be my soldering, a PCB problem or a dodgy processor. But after lots of testing and making up a second one (that behaved exactly the same) I grew suspicious of the ATF22V10C[QZ]s and then found that things were fine using secondhand Latice GAL22V10Bs. Later, after investigating the ATF22V10C[QZ], I found out about the programming instructions described below; those devices also now work fine.

Using ATF22V10C[QZ] devices: "Condition" the device (probably true for any programmer; see below). Select the "UES" profile for the device in the TL866II Plus software when programming them.
References (where I found out about this):

The following link provides useful info about how to correctly program Microchip ATF22V10C[QZ] devices:
http:// forum.6502.org/viewtopic.php?f=10&t=6065&start=30#p7 5562

The conditioning instructions are described near the end of the webpage at the following link, to be used before programming new (and I would assume, "just in case", recently obtained or previously unconditioned) devices:
http://www.bhabbott.net.nz/atfblast.html

[Updated on: Wed, 23 September 2020 13:11]

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Re: New Board Development - SBC6120-RBC Edition [message #7981 is a reply to message #7980] Wed, 23 September 2020 11:59 Go to previous messageGo to next message
tingo is currently offline  tingo
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Useful - thanks!

Torfinn
Re: New Board Development - SBC6120-RBC Edition [message #8024 is a reply to message #454] Fri, 16 October 2020 14:40 Go to previous message
kb811 is currently offline  kb811
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IOB6120

I have just completed building an IOB6120. RTC and battery backup are installed. Everything tested so far seems to be working fine! Things I haven't tried yet are the printer port, the on board serial ports or the digital I/O. Unknown: use of VMAx: from OS/8. I probably need to "exercise" it a bit more.

I constructed Vince Slyngstad's revision of the original that he describes here http://so-much-stuff.com/pdp8/sbc6120/iob6120.php.
The original is described here https://www.jkearney.com/sbc6120/iob6120.htm.
Some additional information can be found here https://tinymicros.com/wiki/IOB6120.
NOTE: Checking the schematics is a must when constructing any of these.

OS/8 boots off a compact flash card in the IOB6120's CF socket (you need to map the partitions first).
There is one known problem: "the Fortran run-time system does not work with the IOB6120"; see http://www.sparetimegizmos.com/Hardware/SBC6120_Adventure.htm.

I wonder if this might be a VT52/IOB6120 "TTY" I/O implementation issue (TBC): whilst I was pondering why Adventure did not work and everything else seemed to, I noted that Adventure seems to be fine if you run the system via the serial port on the SBC6120 (whilst still running OS/8 off of the CF plugged in to the IOB6120). I might see if I can figure out the problem sometime.

Assembly

The PCBs I got back from fabrication had an issue with the silk screen (I don't know why). But everything else seemed to check out okay.

The first mistake I made was using solder paste! There are three SMD components with a very fine pitch, so solder paste and heat seemed to be the best way to go. This worked very well for all the other SMD components, but not the fine pitched ones (stencil, syringe and then just-daub-it-on methods tried). Maybe there was a problem with the solder mask, or my technique.

I gave up on the solder paste and started again with a soldering iron (and another fresh PCB). I used a tip just small enough that it would not immediately bridge multiple pins to solder the fine pitch pins one by one by hand (microscope/visual assistance required for this)! This was much easier than anticipated, although somewhat time consuming. Fingers crossed that all pins are actually soldered down (I double checked with the microscope twice). A very small number of bridges between pins did occur, but were easily taken care of with "solder wick" because I was soldering from the "outside". I also hand soldered all the other SMD components whilst I was at it, except for the crystal. I used solder paste and a hot air station for the crystal as that seemed easier/safer for its style of packaging and device type (but soldering it with an iron would probably have been okay).

The second mistake was the use of shrouded headers for the digital I/O headers (io1 and io2); this is currently preventing me from soldering in the CPREQ jumper extension.

Inter-board connection

I used a stacking header. I couldn't find one with the height and pin length that I would have preferred; so I opted to use two Adafruit headers designed for the Raspberry Pi (one 2x20, and 2x5 carefully cut from another; for extra strength glue was applied to the two ends that butt together just prior to them being soldered in to place). It would be better to have greater separation between the boards (longer header pins) without looking for an additional "stacker" to build it up or needing a shield to prevent shorts (things are particularly close with the socketed crystals on the SBC6120). BTW, stacking them the other way would block direct access to the top of the IOB6120.

Whether, or not, a stacking header is really needed depends on decisions about a front panel .
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