Printer port MMFS boards

[JasonStonier]

Just trying to gauge if there's any interest in this before I do a run of PCBs.

Hoglet produced a Printer Port version of his excellent MMFS and some of the intelligent people on the following thread worked out the hardware using a cheap SD card reader intended for Arduino.

viewtopic.php?f=3&t=17827

I made my own using the notes on that thread, and Hoglet's ROM works brilliantly, and keeps the user port free for other things.

It's a dead easy build, but it would be even easier with a little interface PCB.

Would there be much interest in this? Cost to people in this community would be in the region of:
* £1 PCB only
* £6 built up with the SD card board
* £10 built and supplied with an EPROM

If 5 or more people are interested it would be worth my time designing the PCB and ordering a batch.

[lurkio]

Nice idea! I'd be interested in acquiring at least one of these two built up with the SD card board, please.



EDIT: Sorry to be such a pain, but I've changed my mind. I don't want any of these devices after all. Apologies.

[leenew]

Yeah I would have one too.

Lee.

[Mince]

I'd be interested in a built one without the EPROM. Thanks!

(My soldering is terrible but I can at least burn my own EPROMs!)

[JasonStonier]

So that's 4 of us...probably worth making up some boards then

[flaxcottage]

Make that 5, please.

[JasonStonier]

Make that 5, please.

How did I know you'd soon be along, John

I assume you just have boxes and boxes of gadgets sat around Flax Towers, possibly arranged in the shape of a fort.

[Arcadian]

Put me down for a couple please Jason!

[flaxcottage]

Make that 5, please.

How did I know you'd soon be along, John

I assume you just have boxes and boxes of gadgets sat around Flax Towers, possibly arranged in the shape of a fort.

Yes, I like my gadgets. But I did realise that my post may have been misleading. I should like one only, inclusive of ROM, please. That would make me the 5th person to request one.

One never knows when a gadget such as this can be of use. I have one for my Electron and it is fabulous - I even built that myself.

[JasonStonier]

...I did realise that my post may have been misleading. I should like one only, inclusive of ROM, please. That would make me the 5th person to request one.

Yeah, I got that, thanks

[DaveLecky]

Great idea,

Could you put me down for 2 x built up with the SD card board
and 2 x bare PCB’s.


Thanks

Dave

[lurkio]

If possible, I'd like to have two built up with the SD card board, please.



EDIT: Sorry to be such a pain, but I've changed my mind. I don't want any of these devices after all. Apologies.

[JasonStonier]

Cool. More than enough interest to make it worthwhile then.

Hopefully I'll have time to sort out the design and order some PCBs over the weekend - then two weeks ish for them to arrive on the slow boat.

Just to make sure everyone is aware - this does need a small reversible mod/addition to the beeb, to bring 5V and a clock (I think - Hoglet?) signal to two unused pins on the printer port. It's dead easy if you're even vaguely able to use a soldering iron, or I could very likely sort some grab clips out to do it without soldering - I'll check that possibility when I get the boards and test them.

[lurkio]

Just to make sure everyone is aware - this does need a small reversible mod/addition to the beeb

Is the device Master-compatible?

[hoglet]

Just to make sure everyone is aware - this does need a small reversible mod/addition to the beeb, to bring 5V and a clock (I think - Hoglet?) signal to two unused pins on the printer port.

Not a clock, it connects the SD Card Data Out (MISO) signal directly to Port A bit 7 of the 6522, which MMFS reconfigures as an input. It's done via resistor to avoid any damage when Port A bit 7 is an output (it's default state when the machine resets).

Dave

[lurkio]

Not a clock, it connects the SD Card Data Out (MISO) signal directly to Port A bit 7 of the 6522, which MMFS reconfigures as an input. It's done via resistor to avoid any damage when Port A bit 7 is an output (it's default state when the machine resets).

Is the device Master-compatible?

[leenew]

To clarify:
Could mine be built, with the SD card board please.

I am ever so sorry but I am going to withdraw my interest at this stage.
I didn't read things properly.
Lee

[lurkio]

Oops! I'm withdrawing my interest too. Sorry to be such a pain, but I've changed my mind. I don't want any of these devices after all. Apologies.

[JasonStonier]

No worries - rather you withdraw now than after I've posted them

[rharper]

I'd like a built-up one.
Ray

[Wheel_nut]

Hi JasonStonier,

I thought I'd respond to your Post in KenLowe's thread here so we could continue the discussion on your design.

There were two major requirement which developed from Ken's original (v1) design of his User Port Extender which also provides a power outlet to power other devices on the 1MHz Bus socket.

1. Ken found that with the MicroSD adapter plugged into a 1 x 6 Header on his Board, the MicroSD board drooped at the free end and Ken wants to add a Stand-off pillar to support it.
2. I have been (rather unsuccessfully) playing with KiCAD to design a double headed PCB based on Ken's User Port Extender, to build a versatile adapter to plug into either the User Port or Printer Port. I hadn't spotted that you were also working on a Printer Port adapter at almost the same time!

Ken has indulged me by picking up and running with the double headed adapter and we are currently wrestling with some issues:

1. Trying to keep the board narrow enough to fit into the Master Connector Well (I don't have and hadn't considered the needs of the Master!)
2. Accommodating the need for a Stand-off Pillar at the free end of the MicroSD Card
3. Keeping the Board outline and overhangs free of interference with the Beeb's Connector retaining clips.
4. My obsession with having a single multi-headed Board

Robin

[JasonStonier]

My obsession with having a single multi-headed Board

Most of your list would be met by mine I think - don't have a master to check the clearances, but I'm happy to send someone a board FOC to try and give feedback for Rev 2 if needed.

The single multi-headed board...my personal view is that I don't like multipurpose boards because it's too easy down the line to forget to change 'jumper X' and end up damaging something. Having said that, the beeb new-hardware ecosystem is so diverse, there's a place for all these little mods. As I said in the other thread, I'm doing this for myself and if it further benefits other people I'm perfectly happy.

[JasonStonier]

This is my prototype installed.

The PCB I just ordered is identical in size - except the SD card is on the ‘bottom’, i.e. accessible when you turn the beeb over to view the ports, and I’ve added a header so the VCC and MOSO can optionally be connected with grabber clips instead of soldering the new links.

Does this look like it will fit a master?

[Mince]

Maybe... Here's my Master with one of Steve Picton's MMC User Port boards and a ruler. The side opposite the connectors on the motherboard slopes slightly inwards at the bottom of the trough.

I would say that the MMC board could be about 3mm longer and still fit in the connector (allowing space to slide out the connector and tilt the board out).

[Wheel_nut]

This is my prototype installed.

The PCB I just ordered is identical in size - except the SD card is on the ‘bottom’, i.e. accessible when you turn the beeb over to view the ports, and I’ve added a header so the VCC and MOSO can optionally be connected with grabber clips instead of soldering the new links.

Does this look like it will fit a master?

Have a look in our other thread and you will see pictures that Ken has posted showing his design and a MicroSD card adapter in the Master Connector Well. It is VERY tight and Ken has estimated the limits of acceptable width.

I have just placed an order for some Boards so will race your Slow Boat from China!

Robin

[JasonStonier]

Maybe... Here's my Master with one of Steve Picton's MMC User Port boards and a ruler.

Wow, that is tight. I think I'm 2 or 3mm too deep. Once my boards arrive can I send you one to try a fit?

I reckon I could shave 5mm if I really try, by reversing the connector and overlapping the daughter board - problem is that this might foul the clips on the port...

[JasonStonier]

I have just placed an order for some Boards so will race your Slow Boat from China!

Ooh a competition! I like it. What's the prize?

[Mince]

Wow, that is tight. I think I'm 2 or 3mm too deep. Once my boards arrive can I send you one to try a fit?

...

Of course, let me know when you're ready, or if you want anything else measuring or checking.

[JasonStonier]

[post heavily edited due to a massive error in my pin numbering...]

Great, thanks.

I've added a header to my board so the additional connections can be made by flying leads with grabber clips for anyone who doesn't want to solder to their Beeb motherboard - for the Master, it would be good to just confirm that we still need to pick up on Pin 9 of that VIA for MOSO in a Master.

I'd love confirmation from Hoglet that his P/MMFS will work on a Master with the same connections (Pin 2 on buffer IC70 >> Pin 9 on VIA IC69).

[hoglet]

I'd love confirmation from Hoglet that his P/MMFS will work on a Master with the same connections (Pin 2 on IC70 or Pin 32 on IC69).

Electrically, it should work. The LS244 buffer on the Master is IC5.

I'm not sure anyone has actually tried it though, and on the Master it's easier to add a second user port (e.g. using the Econet header and a board from Steve Picton, which is what I use myself to keep the normal user port free for a mouse).

Dave