Demoboard users have you tried this?

Oldbitcollector (Jeff)

I'm curious if any of the demoboard owners here have tried
to put the SD on the data-lines of the VGA head yet?

I'm going to take a shot at it this evening and see if it's
remotely possible to open some more I/O for you guys.

OBC

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New to the Propeller?

Getting started with the Protoboard? - Propeller Cookbook 1.4
Updates to the Cookbook are now posted to: Propeller.warrantyvoid.us
Got an SD card? - PropDOS
Need a part? Got spare electronics? - The Electronics Exchange

Post Edited (Oldbitcollector) : 5/8/2008 3:07:42 PM GMT

Ken Peterson

Not sure what you're talking about. You mean sharing the same I/O pins for VGA and SD card?

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Oldbitcollector (Jeff)

IIUC, the demoboard has P0-P7 open for experimentation.

What I'm suggesting is the possibility of keeping this open for other things,
like maybe that PropGFX card that Baggers/Coley are working on,
and moving the four required SD connections to points on the VGA head.
I'm picturing a SD card with a male VGA plug, so no, not shared.

Something like I did here with the Atari joystick stuff..
obex.parallax.com/objects/87/

I'm betting we can tap the I/O on that head for SD and open
things up a little more for demoboard users.

Shame I gave the one I had away at a club raffle. [noparse]:)[/noparse] <GRIN>

I'll try this tonight and see if it can be done.

OBC

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New to the Propeller?

Getting started with the Protoboard? - Propeller Cookbook 1.4
Updates to the Cookbook are now posted to: Propeller.warrantyvoid.us
Got an SD card? - PropDOS
Need a part? Got spare electronics? - The Electronics Exchange

parts-man73

I understand what you're trying to do...

2 issues here.

• You need a 3.3V source for the SD card. The VGA plug does have a 5V pin, you'd either need to drop that voltage, with a regulator, zener, etc... or jumper 3.3V in from the header next to the breadboard.
• are resistors inline on the data lines going to effect the data?

Try and see how you make out, I'm curious now. Both if it works in the first place.... and if it does work, does it work reliably?

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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

hippy

Haven't tried it, don't have a demo-board, but cannot see why it wouldn't work. P16 and P17 have just a single 240R in series, the rest 470R and 240R in parallel if lines are driven as pairs (160R).

parts-man73

oh.... good point by hippy...the lines driven in pairs....

you'd have to choose lines that aren't, giving you non-sequential pins. Most, if not all code that I've seen though have had individual assignments for the SD lines, not a range value

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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

jazzed

I'm using the TV summation network on pins 21-23 apparently without trouble (VGA disconnected).
Interestingly, leaving the TV resistors connected does not seem to affect VGA colors.
Not exacly the SD answer but at least a data point.

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jazzed·... about·living in·http://en.wikipedia.org/wiki/Silicon_Valley

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Oldbitcollector (Jeff)

Slight OT (but it's my thread)

The mouse jack (rarely used on my bench) is very accessible as long
as your application doesn't mind a couple pull-downs.

VGA<-->SD next...

OBC

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New to the Propeller?

Getting started with the Protoboard? - Propeller Cookbook 1.4
Updates to the Cookbook are now posted to: Propeller.warrantyvoid.us
Got an SD card? - PropDOS
Need a part? Got spare electronics? - The Electronics Exchange

Oldbitcollector (Jeff)

It's not looking good so far.. PropDOS fails to see the SD card on any combination
of open pins from the VGA head on my Protoboard. At least I've located a couple
that might be useful from the PS2 plugs.

OBC

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New to the Propeller?

Getting started with the Protoboard? - Propeller Cookbook 1.4
Updates to the Cookbook are now posted to: Propeller.warrantyvoid.us
Got an SD card? - PropDOS
Need a part? Got spare electronics? - The Electronics Exchange

hippy

OBC : Try the SD connected directly to the Prop pins rather than VGA connector side to make sure the code works and it is a VGA hardware not a software / configuration issue. You could also try the 'standard' P0-P3 wiring then add the R's to see what breaks things.

Also, the PS/2 are 10K pull-UP ( to 3V3) with 100R in series on DemoBoard and ProtoBoard.

There are two spare PS/2 pins unused which could be re-purposed for SD card use via a PS/2 plug. The few cables I've checked don't have those pins fitted or are not connected, so good if a keyboard or mouse is accidentally plugged-in, but would have to build a PS/2 cable for SD interfacing.