Propeller Motherboard with card slots?

Dgswaner · 2010-05-10 19:51

I would like to implement a motherboard and daughter card architecture for my projects, a while back I was looking in to this, and people have already done this with other Micro processors. but now I can't find any info on it. has anyone done this? I'd rather buy a product than have to make one.

Just to clarify, what I'm looking for is a Motherboard that has 4-5 card slots, and all of the card slots are connected in parallel. the motherboard could have a propeller right on it, or it could be added through a card slot. but the motherboard would supply power for all of the daughter cards. the daughter cards are connected to the propeller through the other slots and the motherbord. this would make it really easy to add/ modify or replace modules of a project. and eliminate a lot of the wires.

does this exist? if so where can I get one?

I'm looking for a card/slot solution not a Pin/header solution.

thanks

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DGSwaner

"When in doubt, use C4" - Jamie Hyneman, Myth Buster

parts-man73 · 2010-05-10 23:18

Most, but not all the criteria you laid out, describe SpinStudio to some degree.

The only issues I see where your requirements are not met are

It's not a card/slot solution per se. The physical connections to the motherboard differ, but to the same end. I had thought about using a card/slot scheme when devising SpinStudio, but I felt that external connections would not be sturdy with cards pointed up at a 90 degree angle to the Mainboard. A real computer motherboard has a screw holding the adapter card to the computer case, whereas the SpinStudio would not have a dedicated Chassis to depend upon for support.
The processor only resides on the Mainboard, although now with the "Marko Module" Propellers can be added to each slot, or "socket" as I call them, for some form of multi-processor functionality.

but I do think it does as you say - "this would make it really easy to add/ modify or replace modules of a project. and eliminate a lot of the wires. "

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Brian

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mikediv · 2010-05-11 01:18

I actually built my own with 4 expansion slots I used the same ones for the Hydra so I could use those cards , it works with any of the Hydra cards I have the 512K ram the 128K the SD card and the a few blank experimenters cards with my own circuits
the only problem is I can only use one card at a time I have to figure out some way to multiplex the I/O I can use the 512K card and one of my Hex display cards because they use different I/O but I would love to see a multibuss system
so I could plug a few of the cards in at the same time . It would be great to have the SD, the Ram and the proto cards all at once

Dgswaner · 2010-05-11 03:35

I did plan on providing a support on one side for the card slots. I do like the idea of card slots better, with some dip switches or some simple wiring, each card could have access to all of the I/O pins, the robot that this is for uses almost all of the I/O's

However, I like your design, I think what I'm going to do is run ribbon cables to some of the modules, instead of having them plugged right into the board. Do you see any problems with this?

@mikediv I'd like to see what you came up with. do you have any pictures? even though I think I'm going to use a Spin studio board I will most likely look it to my own design more.

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DGSwaner

"When in doubt, use C4" - Jamie Hyneman, Myth Buster

Rayman · 2010-05-11 10:11

If you want all cards access to all the I/O pins, I'd suggest taking a look at the Propeller Platform... You can then stack up matching "shields"...

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schill · 2010-05-11 12:14

I've thought of putting together something similar to SimmStick (see www.dontronics.com) for the prop. I've used this stuff with AVRs before. In the end, however, it seems you either end up hardwiring things to specific contacts or putting in a lot of extra hardware just to make the connections you want.

parts-man73 · 2010-05-11 12:44

Dgswaner said...
I think what I'm going to do is run ribbon cables to some of the modules, instead of having them plugged right into the board. Do you see any problems with this?

Shouldn't be a problem. Just put a male 20 pin IDC connector on the modules identical to the type on the Mainboard. Put a note on your order and I'll throw in some extra connectors for you.

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Brian

uController.com - home of SpinStudio - the modular Development system for the Propeller

PropNIC - Add ethernet ability to your Propeller! PropJoy - Plug in a joystick and play some games!

SD card Adapter - mass storage for the masses Audio/Video adapter add composite video and sound to your Proto Board

David B · 2010-05-11 15:50

Here's a link to a full-blown motherboard/backplane project. It's not directly propeller-powered, but I would think that a propeller card could be made to drive a backplane unit like this in the way that you're looking for.

http://forums.parallax.com/forums/default.aspx?f=25&m=423946&g=434873#m434873

I looked into buying an S-100 connector backplane/bus with the same idea as you but wasn't able to find one that seemed suitable.

Too bad - I would think that would be ideal; that way, if there were a standardized pin connection, then anyone could make and sell cards for RAM, parallel ADCs, hard drives, many different larger devices to connect to a propeller.

There's a picture of my homemade propeller-powered parallel bus backplane unit halfway down the linked page - I decided to go with six DB-25 connectors with 3 connectors providing the low 16 IO pins in parallel, and three providing the upper 16 IO pins. Each connector supplies gnd, 3.3, 5 and 12 volts. It's worked very well.

Nick McClick · 2010-05-11 18:22

It's an interesting request - Usually edge connectors are used because they're cheaper and support higher pincounts.

You don't need the higher pincounts with a Propeller, so I think most modular solutions are Pin/header based because of superior reliability and robustness. They're also hobbyist-friendly, you can connect a module to a stripboard / breadboard.

Except for the edge connectors, I think the Propeller Platform or SpinStudio would do everything else you mentioned.

@David - the Propeller Platform is standardized, I sell modules, so does Rayman, Brilldea and The Shoppe at Wulfden. You can grab the documentation and pcb templates here.

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schill · 2010-05-11 18:50

Nick McClick said...
@David - the Propeller Platform is standardized, I sell modules, so does Rayman, Brilldea and The Shoppe at Wulfden. You can grab the documentation and pcb templates here.

And another board (not for sale) may just happen to show up at UPEC.

David B · 2010-05-11 20:40

Nick, I like the idea of the gadgetgangster platform, but the problem I have is that most of the modules look like they cannot be stacked, is that right? So you can't connect multiple modules at the same time. That's a show-stopper for me.

I have several spinStudio boards which I've used quite a lot, but I ran into the same problem with it - once you connect more than three cards (plus the programming card), you've run out of expansion capability.

It's not unusual for projects I work on to use four or five separate devices, like an SD card module, plus a DAC module, plus an ADC module, plus an LCD module, plus a connection to a breadboard where I'm trying some new circuit.

The benefits of a backplane design are that it allows many modules to be connected at the same time, and there is no pin limit on each module, and modules can share pins (which may not be common but is really handy when you need it).

If someone could design a backplane that would plug into the gadgetgangster (or spinStudio) platform, which itself would mount several parallel-connected card connectors like Dgswaner first asked about, (or sockets, which I like to use) I think that would be just about perfect.

Bill Henning · 2010-05-11 20:49

David,

Unless some mechanism is added to multiplex the pins, you cannot put more than one input or output on a pin.

The Propeller does not have a conventional bus like microprocessors have.

It IS possible to define a bus, however you have to define it based on the prop pins, and implement some way deciding which card you want to use.

For one of my commercial products, Morpheus, I have implemented an ISA-like bus, however that is not a general propeller bus, but specific to my products.

I think that perhaps you may have misunderstood how backplanes work; the slots have to be addressable in some fashion.

Best Regards,

Bill

David B said...
Nick, I like the idea of the gadgetgangster platform, but the problem I have is that most of the modules look like they cannot be stacked, is that right? So you can't connect multiple modules at the same time. That's a show-stopper for me.

I have several spinStudio boards which I've used quite a lot, but I ran into the same problem with it - once you connect more than three cards (plus the programming card), you've run out of expansion capability.

It's not unusual for projects I work on to use four or five separate devices, like an SD card module, plus a DAC module, plus an ADC module, plus an LCD module, plus a connection to a breadboard where I'm trying some new circuit.

The benefits of a backplane design are that it allows many modules to be connected at the same time, and there is no pin limit on each module, and modules can share pins (which may not be common but is really handy when you need it).

If someone could design a backplane that would plug into the gadgetgangster (or spinStudio) platform, which itself would mount several parallel-connected card connectors like Dgswaner first asked about, (or sockets, which I like to use) I think that would be just about perfect.

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Phil Pilgrim (PhiPi) · 2010-05-11 21:04

The difficulty with a backplane for a microcontroller (vs. a microprocessor) is that there's no hardware address/data scheme that allows for multiplexing the various cards on one bus. You can program an addressing scheme in software, of course, but you get a huge performance hit as a result, precluding, for example, daughtercards that do video output. So you end up having to pre-assign pins to the various types of cards, which inevitably leads to conflicts. (Parallax tried this with the AppMod bus.)

A scheme that might work better is to have header sockets that provide four signal lines each, plus power and ground. These can be arrayed such that any particular daughtercard can plug into one, two, or four of them, depending on how wide it is and how many signal lines it needs. Then you can mix and match cards of various widths without having to share signal lines, yet still maximize port utilization.

-Phil

schill · 2010-05-11 21:31

I don't think the original post is looking for a full blown bus with data and address lines - just all of the pins available at all connectors. At each connector, you may only be using a few of the pins (which would probably not be used by any other connectors).

I think the idea of address and data lines is "covered" by things like SPI and I2C. I presume that's why they exist in the first place - to allow for addressing devices without required a full bus.

hover1 · 2010-05-11 21:32

I guess you guys have hit on most of the problems. I would add proper termination, (active? static?). Buss systems back in the 70's and 80's had enough problems with 8 Mhz, let alone 80 Mhz.

16K! I only got up to 8K boards. (Altair 8800).
Jim

David B · 2010-05-11 21:45

Bill.

The cards that I've designed that share pins use separate pins for control. I think I have 4 or 5 different cards that all use the low 8 IO pins for a data bus (so the propeller can use the fast "movs" command for byte transfer) but each card has a different pin for device select. I've built cards in the past that used a 74HCT138 to decode a device address, but didn't go that route for these boards.

But what I've found in practice is that most of the time, for the kinds of devices I want to connect to a propeller, full addresseability is overkill. Most things - serial ADCs, DACs, SD cards, serial LCD displays, only use 2 or 3 or 4 lines, and it works quite well to simply assign separate propeller pins to each device and to hardwire the card that way.

But I still like to connect lots of devices, and the backplane works excellent for that.

David

mikediv · 2010-05-11 22:09

Dgswaner,,, I will post some pictures, I have looked at a few of the platforms and they look very efficient , but to be honest I like the old school idea of having a back plane or mother board type I just feel like I have more control..

What I have here is a Prop the basic setup a PIC 16F684 and a MC-6800 with Rom and 64K Sram I still need to add a ton of stuff I am wire wrapping the whole thing I wish I knew how to have my own boards made the like the guys here but I am not there yet.

When this is done I hope to have Prop MCU, , Motorola CPU, one of the smaller 8 bit PIC chips, Sram, Rom , EEprom, Video and Audio , Serial and USB and most importantly the ability to use the Hydra expansion cards and a few of them at the same time I also bought a few of the really tiny Parallax solder-less bread boards I would like to mount one for building my experiments.

I have a schematic of the Micro stuff but I am missing a huge part,,, the expansion buss interface! I need to come up with a way to interface the 4 Hydra slots I have gotten my interface to work with one card at a time I really like your idea about using switches I may borrow that if you do not mind but I would still like to be able to run multiple boards I could put the SD and Sram interface directly on the board but I still want to be able to run , multiple cards even if they are my own stuff.\

Yikes I am sorry about the blurry pictures I will try again ..lol

Post Edited (mikediv) : 5/11/2010 10:14:07 PM GMT

kwinn · 2010-05-11 22:13

No reason you can't experiment with card slots. Here is what I added to my protoboard for prototyping. I generally avoid using P28-P31 if I can, but that gives you 28 pins to use for a general purpose bus. Use 4 short 16 pin ribbon cables to connect to a perf board and you have a motherboard with:

- ground, 3.3V, and 5.0V available
- 8 data lines (P0-P7)
- 16 address lines (P8-P23)
- 1 RD/WR line (P24)
- 1 Strobe line (P25)
- 2 lines left to use as address lines, to simplify address decoding, or whatever you require.

So far I have used a maximum of 24 lines to read data from eproms so I can transfer it to eeproms.

Nick McClick · 2010-05-11 22:26

@David B - a few modules have to go at the ends of a stack (DMXIO, LCDUI, El Jugador), but most (Prototyper, ProtoPlus, OctoDriver, Pixter X, Prop Platform, Termboard, battery) fit just fine.

In the microcontroller world, I think i2c is the sweetspot for buss-style development. There's just too much overhead (on the electronics side and on my brain) with more complicated, non-standard addressing schemes.

Of course - whatever floats your boat. It's always interesting seeing the development take place.

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Bill Henning · 2010-05-11 22:34

Dave,

I agree - it is very useful. I prefer (at this time) to use stacking connectors, as then I avoid the need for a dedicated motherboard. My designs tend to be able to stack on each other <grin> so for example, I can use a Propteus as an I/O processor for a Morpheus, or up to three FlexMem's on P0-P7.

As you said, a 74xx138 can be used as an address decoder for up to 8 devices, or two of them for up to 16 (as 74xx154's are becoming rare)

I totally agree that for everything except very high speed I/O, SPI and I2C are the way to go (and save a lot of pins).

Bill

David B said...
Bill.

The cards that I've designed that share pins use separate pins for control. I think I have 4 or 5 different cards that all use the low 8 IO pins for a data bus (so the propeller can use the fast "movs" command for byte transfer) but each card has a different pin for device select. I've built cards in the past that used a 74HCT138 to decode a device address, but didn't go that route for these boards.

But what I've found in practice is that most of the time, for the kinds of devices I want to connect to a propeller, full addresseability is overkill. Most things - serial ADCs, DACs, SD cards, serial LCD displays, only use 2 or 3 or 4 lines, and it works quite well to simply assign separate propeller pins to each device and to hardwire the card that way.

But I still like to connect lots of devices, and the backplane works excellent for that.

David

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Oldbitcollector (Jeff) · 2010-05-12 00:00

@mikediv

That's quite a work of art! Thanks for sharing.. Any chance at a peek at the bottom? [noparse];)[/noparse]

OBC

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mikediv · 2010-05-12 00:03

Kwinn I always wondered if you ever got that to work( the reading an eprom) I don't know if you remember but you were trying to help me out to do the same thing .. I never got mine to work I think my circuit was OK I was trying to read a 2764-256 but I am very green to programing so bluntly put I failed .. Can I ask which eprom you were able to read. Also I forgot to mention I wanted to add VGA to my project I kind of ripped off the Hydra design for the prop portion so I really do not have many I/O lines left.
If my memory serves me ( and it probably doesn't) were you working a multiplexing scheme to expand the I/O?

lynchaj · 2010-05-12 11:41

Dgswaner said...
I would like to implement a motherboard and daughter card architecture for my projects, a while back I was looking in to this, and people have already done this with other Micro processors. but now I can't find any info on it. has anyone done this? I'd rather buy a product than have to make one.

Just to clarify, what I'm looking for is a Motherboard that has 4-5 card slots, and all of the card slots are connected in parallel. the motherboard could have a propeller right on it, or it could be added through a card slot. but the motherboard would supply power for all of the daughter cards. the daughter cards are connected to the propeller through the other slots and the motherbord. this would make it really easy to add/ modify or replace modules of a project. and eliminate a lot of the wires.

does this exist? if so where can I get one?

I'm looking for a card/slot solution not a Pin/header solution.

thanks

Hi!· You might want to check out ECB (Eurocard Bus) by Kontron.· It was used for embedded control applications during the 1980's and 1990's in Europe.· What makes it special is that it uses common off the shelf parts to accomplish what you describe:·Eurocard boards (160x100 mm standard size) with DIN 41612 64 pin (AC) or 96 pin (ABC) connectors.· This is a highly reliable and durable bus structure.· Couple with the signal mapping from a Z80 for the ECB standard and you've got a really solid bus.

On the N8VEM project we use the ECB for the backplane.· All the boards plug into the ECB backplane and the SBC controls the bus.· Since all the boards are of the same common format (Eurocard) it keeps the design consistent and low cost.· Currently the main SBC is Z80 based although there is one Propeller board.· The bus could be readily extended to a Propeller.

You are welcome to check out the N8VEM project to see if there is anything which could be helpful.· The PropIO board may serve as a good starting point for a Propeller based project.· Just do an internet·search on N8VEM and it will show the mailing list and wiki.

Good luck!· I hope this helps.· Have a nice day!

Andrew Lynch

Leon · 2010-05-12 15:01

Half-size DIN41612 connectors are available. I have some 32-way ones that I got for a similar application, but I've forgotten what it was. They might be useful for a Propeller bus system - 30 lines + power/ground.

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Leon Heller
Amateur radio callsign: G1HSM

Post Edited (Leon) : 5/12/2010 3:07:16 PM GMT

kwinn · 2010-05-12 16:06

@mikediv, yes I got it to read eproms. It consists of a small board with 5 74HC541 buffers that connects to my protoboard by 4 short 16 pin ribbon cables. The power (+3.3V and +5V) comes from the protoboard. So far I have used it to read 2708, 2716, 2732, and 2764 eproms but there are enough address lines for 64Kx8 (27512). I have only used it to program a 512Kb (64K x 8) eeprom.

As for the multiplexing scheme, I think that was a discussion related to adding external memory to the prop for LMM and emulations.
If I were to build another eprom reader/eeprom programmer I would use either:

1 - '595 S-P shift registers for address and data out, and '597 P-S shift register for data in.
2 - 2 '393 binary counters for address, 1 '595 S-P shift register for data out, and '597 P-S shift register for data in

Much simpler wiring, fewer prop pins required, and not that much slower from my standpoint. I would probably go with #2 - it is the faster one.

It also needs a few jumpers to accommodate the different pinouts of the chips.

Dgswaner · 2010-05-12 19:45

Wow this Thread really took off in a different direction! just to Clarify I was not looking for a BUS type system, just merely a system that would allow me to use all of the I/O pins.

I placed an order for the PropStudio and some of the Daughter boards, Prop platform or what ever it's call from gangster gadget was more expensive and didn't have the modules that I was after. beside it looked like you could only stack 1 or 2 high. which I guess isn't the case. and that I already own 2 boards for the PropStudio.

I think I'm going to work on an in house board tho. I can make boards fairly easily, and it would be nice to say ok for this project I need audio, network and an SD card, and have the electronics build in a few hours instead of having to design custom PCB's or hand wire something.

anther handy aspect of a card slot and the prop studio and others are for debugging, one quick add-on and I have video output. or VGA. with out having to wire it up on a protoboard. once the problem is solved that part is removed.

Thanks for the input!

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DGSwaner

"When in doubt, use C4" - Jamie Hyneman, Myth Buster

schill · 2010-05-12 19:50

When I was thinking about doing something like this, I came to the conclusion that I would not want to use card edge connectors. If you use them, then you need cards specifically designed with them in mind. You need the correct contacts (spacing, width, extent, etc.) and in many cases a specific board thickness (or need to be within a specific range of thicknesses). While they certainly exist, typically the price is quite a bit higher.

I figured I would just use right angle headers (single row) with male headers on the cards and female headers on the "motherboard." These are pretty cheap and you have a lot of board options - off the shelf or custom.

Dgswaner · 2010-05-12 22:29

I'm not thick headed enough to insist on card slots when enough people have provided reason Pin headders will work just as well in not better. I have to say Card slots do add to the "Cool factor".

I found a solution for my current project, with plans to come up with my own MB solution.

On that note, from reading all of the comments I think schill nailed my thoughts, Card slots are not the way to go, however I think I will opt for a double row, not single. I might even be able to make it Prop Studio Compatible, by putting 90deg. connector on his boards. using his shorter header into a longer socket I would be able to use any of the pins that I want, especially with them in parallel. Ucontroller boards are very reasonably priced and it doesn't make sense to spend an hour or 2 making a board I can get for $10.00.

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DGSwaner

"When in doubt, use C4" - Jamie Hyneman, Myth Buster

kwinn · 2010-05-13 04:04

Double row pin headers would be the way to go in my opinion. With the pins on the add on cards you could even use ribbon cable with female connectors instead of a motherboard. There is also a large range of pin-outs ( from 10 to 50 pins) to meet your needs. I use 4 16 pin (male) headers on my protoboard and a 50 pin (male) header on my eprom/eeprom board. Very easy to split the 40 pin ribbon cable into 4 sections to connect to the protoboard and pick up all the signal and power required.

Post Edited (kwinn) : 5/13/2010 12:53:03 PM GMT

Propeller Motherboard with card slots?

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