Home » RBC Forums » General Discussion » Multicomp PCBs
| Multicomp PCBs [message #103] |
Tue, 01 December 2015 07:12  |
lenzjo
Messages: 5
Registered: November 2015
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Junior Member |
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Hi,
I've just got a Cyclone II board and would like to build a 6809 system with it. I noticed mention of some pcbs for it in the wiki. Are these pcb's still available?
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| Re: Multicomp PCBs [message #105 is a reply to message #103] |
Thu, 03 December 2015 16:45  |
nealcrook
Messages: 127
Registered: October 2015
Location: UK
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Senior Member |
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Hi Lenzjo,
the Cyclone II PCB "motherboard" was available from http://www.smarthome.jigsy.com/fpga but the designers (Dr Acula and James Moxham) have now moved on to a PCB designed for a different, Cyclone IV-based daughtercard. You can try contacting them to see whether they still have any of their older design available.
If not, it's fairly straightforward to construct this system using a prototyping board. I used point-to-point wiring with (soldered) wire-wrap wire. It's about 45 wires. Use Grant's diagram as a guide:
http://searle.hostei.com/grant/Multicomp/index.html
The end result is not beautiful but it's All My Own Work:
https://github.com/nealcrook/multicomp6809/blob/master/photo s/re_20150429_multicomp.jpg
For the RTL itself, since you want a 6809 system, I suggest you use my updated set of files which you can find here:
https://github.com/nealcrook/multicomp6809/tree/master/multi comp
With this hardware setup, you can run the following software:
Brad Rodriguez's Camel Forth (I use this as the ROM "boot monitor" and everything else is loaded and started from images on SD card)
Microsoft 8K BASIC
Lennart Benschop's 6809 debug monitor, BUGGY
Dave Dunfield's CUBIX
FLEX 09
Nitros9 (level 1, currently)
images for all of this and source code for (nearly) all of this is available here:
https://github.com/nealcrook/multicomp6809
and documentation here:
https://github.com/nealcrook/multicomp6809/wiki
The Nitros9 sources are not on-line but the executable disk image is online and the sources (as a patch from the open-source repository) is available from me on request.
If you have any problems getting up and running or in following any of the documentation on my wiki, let me know; I'm always keen to facilitate bringing another 6809 system into existence.
Neal
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| Re: Multicomp PCBs [message #112 is a reply to message #111] |
Wed, 09 December 2015 02:02 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Member |
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My original boards added a touchscreen, which I always had hopes of getting working but the code didn't quite fit on a cyclone II so all of that part of the board is not needed. Hence the move to the cyclone IV. Just now I costed out the real cost of a cyclone IV kit. With all the parts, including three serial ports, dual ram, wifi access and cyclone IV fpga, it comes to $120AU, maybe $100US. I'm putting together some kits right now and should have them available soon. One big plus for me is Max's software where he puts partitions on an SD card so one card can do CP/M2, CP/M3 and MP/M plus software to easily copy between FAT and CP/M partitions.
Having said all that, the cyclone IV project has different pin layouts due to the FPGA board, so the 68xx part of Grant's original project has been left behind. Given this discussion, I thought it well worthwhile to go back to Grant's original design and do another PCB. The cyclone II fpga is cheaper, there are less parts on the board and an complete kit would be cheaper too.
I've got a PCB designed just tonight. It is 10x10cm, and is pretty much exactly the same as Grant's webpage http://searle.hostei.com/grant/Multicomp/index.html except for i) the serial ports also include max3232 chips for proper RS232, and ii) one pulldown on the NC pin 1 of the ram chip which means the socket can take a 128K or a 512K ram chip.
The thing is I am 99% sure that this pcb is correct but not 100%. It is based on version 9 of boards I already made and those 9 versions ironed out a lot of bugs, including things like flipping the fpga board upside down and adding two pins for power. It uploads fine to Seeed PCB and the processed gerber looks correct. The quote is $21.90 for 10 boards (minus shipping).
So the next step. I'm happy to send this pcb package to anyone and you can get your own boards made, but no guarantee it is perfect. If you want to do this, log into Seed and upload the attached zip file.
Or I can get boards made and we wait a few weeks and I can post them out, which of course will be cheaper but will take longer.
There probably is a market for Grant's original design as it is, because it is cheaper than the cyclone IV option. Though you need an obsolete version of Quartus to program it and the fpga is pretty much full, so clever things like MP/M and more serial ports run out of room.
In an ideal world, I think there is a place for both the cyclone II and IV, and as prices come down, maybe someone might port over the 68xx part of Grant's project into the cyclone IV (not me though, I'm more a Z80 sort of bod!).
Cheers, James Moxham
[Updated on: Wed, 09 December 2015 02:14] Report message to a moderator |
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| Re: Multicomp PCBs [message #113 is a reply to message #112] |
Wed, 09 December 2015 04:38 |
nealcrook
Messages: 127
Registered: October 2015
Location: UK
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Senior Member |
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Hi James,
nice work in recreating a smaller version of your original. Are you working to a fixed board size? I'd (respectfully and politely) lobby for the following changes:
1/ add a second RAM device like your original board (it looks like this might fit if you rotated the MAX devices and switched to a mini SD socket). Routing should be straightforward because you can arbitrarily scramble address and data lines to the RAMs
2/ add the option to power the keyboard from 5V rather than 3V3 (power jumper plus 2 optional diode clamps as suggested by Ian May)
3/ 2-pin jumper connecting pin <cannot remmmber offhand> to Gnd. In my 6809 codebase, as deployed by Kip Koon, I used that to swap the address decode of UART1 with the virtual uart (VGA/PS2). This allows the system to selectively boot to either device with no sw change
4/ 4-pin header to support connection of RTC chip + button cell (ebay module)
If you're open to any of these suggestions I'd be happy to provide more details and/or review schematics/layouts. I'd be interested in one or two of such boards and would be willing to fund a purchase of 10 (in the UK).
I see that you have 5V on this board, for the MAX devices. Is there a connection on the FPGA daughtercard header to route power up (I don't recall seeing one) or do you need to use separate power connection to the FPGA daughtercard?
My current 6809 codebase, compared with Grant's original, includes a GPIO module, interrupt controller, memory mapper, timer and hardware single-step support and more synchronous timing. The FPGA has not yet declared itself "full" but it is pretty close.
thanks,
Neal.
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| Re: Multicomp PCBs [message #114 is a reply to message #113] |
Wed, 09 December 2015 04:55 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Member |
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Hi Neal,
Thanks for the suggestions.
0) The board size is 10x10cm because Seeed charge in 5x5cm increments and going to 10x15cm is quite a bit more so I guess that is the thinking. Plus for some very strange reason, my local post office charges more that double the price of postage to the USA for a 10x15cm board cf a 10x10cm one. It goes over a weight threshold. On the cyclone IV we put things in the middle of the fpga chip and there is spare room too on this cyclone II so we can fit things in the middle there too. So there is spare space for (fairly low-rise) things.
1) Second ram kind of led us (me and Max) down the path of how do we use the second ram, and that led to a MMU using both MP/M and a ram drive at the same time and that led to more vhdl which pushed us to the cyclone IV. There probably is a cunning way to put in a MMU in the cyclone II but might mean only one serial port. There is another idea - Grant's board only used 64k of a 128k chip, but with three jumpers to three spare fpga pins it would be possible to use the same 32 pin ram socket to use a 128k chip or a 512k chip, and so go from 64k to 512k with just one chip. Is this enough to do clever things with a 6809?
2) Happy to take suggestions about the keyboard power. Ian did lots of research on this. Grant's design powers from 3V3 but can easily change to 5V. Or put in two jumpers for either/or.
3) Can you post a schematic for that - should be ok to do.
4) Sounds a good idea, have you got a schematic?
In general, Grant's design has lots of spare pins and so extras should be possible if they can fit in 10x10cm. I'd very much prefer that everything stay backwards compatible with Grant's original design, but then add in things that add extra value but which can be left off a board if not needed.
5) Power is 5V, this goes to the fpga which has a local 3V3 regulator. I don't think anything on the board is powered by 5V except the fpga. Oh and one pin on the VGA which tells the display it is enabled (and which Grant leaves not connected, not sure about that...) Max3232s are powered by 3V (max232s are 5V).
6) Your 6809 sounds brilliant and is exactly the sort of addon that this design needs. In an ideal world, I'd like a board that is Grant's original design, adds in your extras and is all backwards compatible.
Great fun brainstorming this - I look forward to adding in your suggestions 
Cheers, James
[Updated on: Wed, 09 December 2015 05:10] Report message to a moderator |
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| Re: Multicomp PCBs [message #115 is a reply to message #114] |
Wed, 09 December 2015 12:40 |
nealcrook
Messages: 127
Registered: October 2015
Location: UK
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Senior Member |
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Hi James,
thanks for your explanations. I agree that your rationale for keeping the board size down is sound, and I agree that a board that works with Grant's original design is highly desirable.
Here is a (sorry, hand-drawn) schematic showing RTC dimensions/hookup, kbd connections and the uart address jumper. Also (if there's room..  a connector for 8 GPIO which are software accessible in my design. I showed the dimensions of the RTC module. It would be OK to fit this on the bottom of the board (mirror the connector). Search in ebay.co,uk "arduino rtc ds1302" for a picture.
My code-base does include a memory mapper that has 2 contexts and can map up to 1MByte of SRAM in 8K chunks. It also has the ability to disable the ROM, making the whole address space appear as RAM (apart from the 16-byte memory mapped I/O space (yes, yes, memory-mapped. No sniggering from you z80 types!! . The memory mapper has been designed to be functionally compatible with that on the Tandy Coco, with the hope that it will allow a level-2 port of NITROS9 (I already have a level-1 port running). As I mentioned, it does all fit along with the VGA color display, 2xUART, GPIO etc. (I guess a 6809 is somewhat smaller than a z80).
That is why I would lobby for (i) connecting all the address lines to the existing RAM (ii) adding a second RAM if it is at all possible. However, I guess that worst-case, a second RAM could be added by piggy-backing and a flying lead for the extra chip select.
I understand that wiring the extra address lines for the RAM would break compatibility with Grant's design, in the sense that his project would need a couple of 1-line additions in order to work with a 128Kx8 device, but I think it's too sad to pass up the opportunity to access 1MByte of RAM. It was my unhappiness at tying off the high-order address line of the AS6C1008 that led me to develop my mk1 memory mapper, then learning about NITROS9 led me to redesign it to accommodate a bigger address space and the capabilities required for NITROS9.
regards,
Neal.
[Updated on: Tue, 18 October 2016 00:05] Report message to a moderator |
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| Re: Multicomp PCBs [message #119 is a reply to message #115] |
Wed, 09 December 2015 15:51 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Member |
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Hi Neal,
Thanks for the great schematic.
I've added the changes - please take a look and let me know. Which pins do you want to use for A16 to A18?
Cross post with your one above, yes, once get the schematic right can look at layout. And yes, if the fpga overhangs the side of the board, better access to the programming socket, and it may well free up space for that second ram chip. However, then no access to the two 5V supply pins. Would need flying leads. Or maybe some other solution...
[Updated on: Wed, 09 December 2015 15:55] Report message to a moderator |
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| Re: Multicomp PCBs [message #122 is a reply to message #121] |
Thu, 10 December 2015 04:37 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Member |
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Thx for the layout. Ok, maintaining the backwards compatibility but adding extras...
1) overhang the board upside down. One disadvantage - board overhangs. But advantages - frees up some space on the pcb for a second ram chip, frees up space to attach the jtag programming header, and doesn't need to use tall headers (which are a bit hard to find anyway as dual row, so need to use lots of single row ones. Standard height ones are much cheaper than tall ones.
2) add one jumper cable like you say, to bring out the 5V onto the board. Leave it out if not using any 5V things (keyboard mainly).
3) This frees up some space for the second ram. It is entirely optional but also completely backwards compatible with Grant's original design.
4) Yes agree that header is not needed for the NC pin on the 128K ram chip. Is easy to add the pads though on the pcb and they don't cost anything. Realistically, many folks might be tempted to use a 512k rather than a 128k chip as they are almost the same price and then you have the flexibility to do more things. Just bridge the pads with solder.
5) Changes on the attached pdf are i) adding the second ram chip and ii) deleting the power jack on the board.
I need to remind myself that now need to design the board so the cyclone II power jack doesn't get blocked by anything on the pcb.
Is this all ok?
[Updated on: Thu, 10 December 2015 04:54] Report message to a moderator |
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| Re: Multicomp PCBs [message #128 is a reply to message #124] |
Fri, 11 December 2015 02:28 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Member |
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Hi Max,
Great ideas there.
1) CTS to each port. Yes, can do that.
2) USB connector removed.
3) See below brainstormed a bit more
4) I might need to think about that. See the posts above, ended up removing the supply jack off our pcb and using the supply jack on the cyclone ii board instead. So then 3V and 5V comes off that board onto our board.
5) I2C is on the 'to do' list. But it has been on there forever... The RTC on this board is at least a working design with software written as per previous posts. Or maybe we do both? Adding I2C is really just a matter of declaring two pins on the cyclone II to be I2C and adding a couple of 10k pullups to 3V. So it is really just a header and two resistors.
6) some general I/O pins on this board already done, but might run out of pins if we start adding I2C and CTS. Will need to check...
I like this idea of having things all along one edge and maybe it can be done with a 10x10cm format. Hmm - , that is going to be vga, keyboard, one serial port and sd card? When I get home i'll test that out. I have ordered some little micro sd sockets on pcbs - they actually end up cheaper to buy now that a standard sized sd socket. That makes the sd part smaller. The 'single edge' design becomes more feasible.
Technically, if we are replicating Grant's project, he doesn't have either serial port converting to RS232 levels, and brings out both as TTL. So..., keeping to that philosophy, it should be quite possible to bring all the I/O to one edge. Maybe one D9 RS232 and one TTL serial port - that could be a good compromise.
I'll see if it fits. If it does, the ram chip (s) probably will end up some distance from Grant's original location, which then means it doesn't matter any more about the cyclone ii being flipped. The autorouter is easily completing on Eagle in under a minute or so.
@Max, what would be really cool would be to bring as much as possible from the cyclone IV project back to this cyclone II project. Especially your boot monitor, your multiple partitions on an sd card, and your diagnostics. They make setting up and testing boards a breeze and it is so nifty to be able to copy CP/M files between partitions rather than downloading them via serial. I think you free up some fpga space by moving some of the bootloader into the sd card. So maybe there is room in the cyclone ii for at least vga, keyboard, two serial and ?? the MMU
If it almost fits but not quite along one edge, can also move the 2 corner holes in maybe 2cm so the full 10cm is available.
[Updated on: Fri, 11 December 2015 02:35] Report message to a moderator |
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| Re: Multicomp PCBs [message #129 is a reply to message #128] |
Fri, 11 December 2015 04:48 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Quick experiment with the PCB layout trying to get all the important things along just one edge.
If move the mounting holes back, then it is possible to get VGA, then Keyboard, then one D9, then a micro sd board just to fit in 10cm.
The micro sd module is this one http://www.ebay.com.au/itm/New-Mini-SD-Card-Module-Micro-SD- Card-Module-/201107614941?hash=item2ed2f2acdd:g:j64AAOSwcnpT mVk8
So - TV not along this edge. But ?? if you needed TV it is just two wires and may as well put a RCA socket on a front panel of a box and solder two wires over.
And the second serial port can be TTL.
The cyclone II extends off the side of the board. So can the RTC. And there could well be enough space on the board for a ESP8266 wifi module, which also should extend off the board so less interference to the antenna. Can have 3 jumpers so can connect to the second serial port. So this could add wifi.
On Grant's board he leaves 16 pins free - pins 40,41,42,43,44,45,47,48,51,52,53,55,57,58,59,60
In posts above we have allocated pins 40,41,42 to the RTC and pin 48 to VDUFFF0. And pins 51 to 60 as general purpose I/O pins to a header. So that leaves 4 pins free. Is it ok to allocate 2 of those to CTS on serial ports for full flow control, and another 2 to an I2C bus?
All still fully backwards compatible with Grant's design. Just bringing things out to headers and they can always be used for other things anyway.
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| Re: Multicomp PCBs [message #130 is a reply to message #129] |
Fri, 11 December 2015 05:21 |
nealcrook
Messages: 127
Registered: October 2015
Location: UK
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Senior Member |
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Hi James, Max,
That is all sounding good. In particular, having 1 DB9 and 1 header sounds even better than 2 DB9, given that most PCs don't have RS232 so that many people will need a converter at one or other end of the cable. Please can the DB9 be "port A" (pins 103/104).
Would it be possible/worthwhile to add a 6-pin header for both serial ports, so that the Maxim/DB9 could be omitted? I haven't used any RS232 to date so I don't have a strong feeling on this, just trying to keep all the options open (after all, the autorouter doesn't sound as though it's even breaking a sweat on this, yet)
For the 6-pin header, the 3v/5v selection could be just as planned for the kbd socket. @Max: the current "plan" is to require a flying lead to grab 5V power from the FPGA card (requiring the 2-pin 5V connector on the FPGA card to mate with the 10x10 board constrains the layout too much).
Allocating the 4 spare pins to CTS and "I2C" sounds perfect.
For the RTC module, I have a mild preference for it not extending over the edge of the 10x10 -- eg by mounting it on the bottom of the board. My reasoning is that I think it's easier to get a good mechanical connection - using a 2-sided sticky foam pad. Admittedly the 10x10 then needs to be on stand-offs to keep the whole thing stable. (Of course, in the end it's your call as you are the one doing the work..)
BTW: I zoomed in and didn't like the look of the soldering on that micro sd module!
Neal.
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| Re: Multicomp PCBs [message #137 is a reply to message #128] |
Fri, 11 December 2015 11:29 |
mscane
Messages: 111
Registered: October 2015
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Senior Member |
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I would stick to the normal SD card connector. Those micro SD cards are too small and fiddly. Rather than put is on the back of the board put it on the front like the current Cyclone II board. That makes it easy to access and keeps the size of the board small.
So on the front you would have SD card. reset, leds etc
On the rear you would have VGA, Keyboard, DE-9. The TTL serial port doesn't have to be on the edge
That should work with 10x10.
I have a Cyclone II version of my new software pretty much working at the moment. I had to remove a few goodies (like the baud rate generator etc) but it is compatible with the Cyclone IV system. You can put the SD card in either board and boot CP/M without any problems.
Cheers!
[Updated on: Fri, 11 December 2015 11:29] Report message to a moderator |
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| Re: Multicomp PCBs [message #138 is a reply to message #137] |
Fri, 11 December 2015 16:15 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Member |
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Thanks for all those suggestions. This board is going to be brilliant!
Agree with the micro sd socket comments including the dodgy soldering - ok, stick with the standard size one.
Changes on this schematic are:
1) added 2 pins for reset (bring out pin 144 which is the board's reset)
2) I2C
3) remove one max3232
4) added 6 pin headers for TTL serial for both ports.
5) Added some 4 pin headers in the supply section for 5V, 3V and Gnd (always handy to have)
6) Added 3 leds - duplicates the ones on the cyclone ii board. Can be handy for diagnostics.
Plan is that on the back of the board, VGA then Keyboard, then D9 and on the front of the board, SD leds, reset, and TV.
Attached - preliminary PCB layout. It all fits and autoroutes. The RTC is a large module - would it be ok if it sits over the ram chips? Maybe on taller headers, or two headers stacked? Can then avoid overhang, stick it to the top of the ram chips and it doesn't take too much pcb real estate.
Addit: Fixing Leds - they are active low on the cyclone II.
[Updated on: Fri, 11 December 2015 17:24] Report message to a moderator |
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| Re: Multicomp PCBs [message #141 is a reply to message #140] |
Sat, 12 December 2015 16:11 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Member |
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Good idea re the data bus. I hope it is ok, the autorouter is just starting to struggle so I brought out the data bus as 8 pins on a physical header just near the data bus on the cyclone II. Ended up with short traces. Ditto the reason the GPIO header is where it is. So they aren't near each other, but shouldn't matter much and like you say, could create a nifty expansion bus with those two.
I managed to find an extra 0.05" above the vga and serial connectors, is that enough?
Any other suggestions/changes from anyone?
[Updated on: Sat, 12 December 2015 19:32] Report message to a moderator |
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| Re: Multicomp PCBs [message #147 is a reply to message #146] |
Sun, 13 December 2015 04:57 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Thanks ++ Neal.
I think all of those should be possible. I have work commitments for the next 48h but after then should have some time to make all these changes. Re points 6 and 7, do you mean make the 3V an 0V traces thicker?
[Updated on: Sun, 13 December 2015 04:58] Report message to a moderator |
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| Re: Multicomp PCBs [message #167 is a reply to message #154] |
Mon, 14 December 2015 05:56 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Hi Neal,
Wow, great list there. I have been through it one line at a time, *hopefully* have left nothing out!
Aoutorouter is on 12 mil for the data lines and 25mil for the ground and 3V lines - that is about the best it can do. Anything more than 25mil for power and it fails. Adding a ground plane also fails with polygons that fall apart. So the whole decoupling star thing is going to be hard unless hand rout it all. Which is the difference between 1 minute and many days. My experience though with much more complex boards with many more chips is the decoupling and ground bounce seems ok, so long as decoupling randomly placed around the board so average trace length is low to a 0.1. I think the SD needs 0.1 and 470uf near it - have learned that the hard way. The sp3232 ends up with short traces, and it is really just the ram chip where the decoupling is not perfect. However, multiple boards on the cyclone II and IV seem ok with the less than perfect autorouter.
The attached files are .bmp so can zoom in better than jpg. Lots of updates on the schematic. The gerber is downloaded back from Seed and they always seem to make the fonts slightly larger so have tried to allow for that.
Have changed the title so leaving out my name and replacing it with www.retrobrewcomputers.org. This board truly is an international joint effort now
I had a PM about the eagle source code - this is attached below as well. It will likely change, but at least here is a snapshot for anyone who wants to fork this. This project is open source.
Please let me know if I have left anything out.
[Updated on: Mon, 14 December 2015 06:05] Report message to a moderator |
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| Re: Multicomp PCBs [message #186 is a reply to message #103] |
Wed, 16 December 2015 01:51 |
dr_acula
Messages: 68
Registered: October 2015
Location: Adelaide
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Ok, I'm kind of stuck with that modification.
Sparkfun sell two products - this TTL cable https://www.sparkfun.com/products/9717 and they say "This cable has almost the same pinout and functionality as our FTDI Basic Breakout board" and link to this board https://www.sparkfun.com/products/retired/8772
But the operative word there is "almost" because one is bringing out the CTS/RTS pair and the other is bringing out CTS and DTR. Going back for years, I think picaxe and arduino and basic stamp have used DTR as their reset pin. Probably because it was never used for anything much on a RS232 link so the pin was kind of spare.
Go to ebay and search with FTDI board or cable or breakout and there are a whole range of modules that come up that are meant for arduino, and they are all using the DTR pin. A 'proper' cable would bring out eight pins but they all seem to bring out just six. Sort on price and the cheapest cable that brings out the RTS/CTS pair we want is this one http://www.ebay.com.au/itm/FTDI-FT232RL-USB-to-Adapter-Modul e-USB-TO-TTL-RS232-Arduino-6Pin-Cable-/191732706593?hash=ite m2ca428ed21:g:bM4AAOSwo0JWPH4b
But the order of the pins is
Red wire： 5V
Black wire： GND
White wire： RXD
Green wire： TXD
Yellow wire： RTS
Blue wire： CTS
Different to Max's suggestion, different to the board we made and different to sparkfun's.
Also, some boards are 5V and some are 3V so it is not going to be a 6 way header but more likely individual jumper leads with power not connected? In which case it doesn't matter what order the pins are, so long as they are clearly labeled.
Hmm, now I'm thoroughly confused.
[Updated on: Wed, 16 December 2015 02:06] Report message to a moderator |
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