Propeller Professional Development Board Question

wdfreemanjr

Hello,

I recently purchased a PPDB and discovered that it would take 30 pins to use the Sixteen-segment display using Steve Stuart's Propeller Object. I was a little disappointed to find that my PPDB would be practically useless with only 2 remaining pins if used it to display data. I guess I assumed that there would be a co-processor for the display since it is a professional development board.

If I am incorrect in this assumption, please let me know. If not, is there a Parallax co-processor/daughterboard or other solution that will work with the PPDB that only requires a couple of pins to display data?

Thank you

Oldbitcollector (Jeff)

How about adding a 4x20 serial LCD display to your kit?

Easy to use and only requires a simple connection.

http://www.parallax.com/StoreSearchResults/tabid/768/List/0/SortField/4/ProductID/51/Default.aspx?txtSearch=serial+lcd

OBC

Bean

Just a thought, but you could use a "4 to 16 decoder" and free up 12 I/O pins. You would need to modify the code also to scan by segment instead of by digit.

Bean

wdfreemanjr

Thank you OCB and Bean for your nearly immediate responses. While I like Bean's solution, I don't have the time to get bogged down with data display, as my project is much higher level, so I guess I will go with OCB's solution. Still a little disappointed with the PPDB's included display. It should come with display circuit for the price. Just my 2 cents.

Thanks again.

w4fej

wdfreemanjr wrote: »

Hello,

I recently purchased a PPDB and discovered that it would take 30 pins to use the Sixteen-segment display using Steve Stuart's Propeller Object. I was a little disappointed to find that my PPDB would be practically useless with only 2 remaining pins if used it to display data. I guess I assumed that there would be a co-processor for the display since it is a professional development board.

If I am incorrect in this assumption, please let me know. If not, is there a Parallax co-processor/daughterboard or other solution that will work with the PPDB that only requires a couple of pins to display data?

Thank you

I also have the PPDB and I am driving the displays (all of them) with only 23 pins?? Not sure how you came up with 30, but 23 covers all the pins on my board necessary to drive them. The scrolling marquee really looks neat..

I forget the object I downloaded from the exchange but it worked without modification.
Mike B.

eod_punk

I agree that the PPDB should have come with something to drive the 7 segment displays, but it doesn't so you need to figure out your options. The LCD would use the least number of pins, but if you really want to use the 7 segment displays I would suggest using a MAX7219. It can drive up to 8 common cathode digits while only using 3 pins on the propeller. Good luck on your project!

Bean

I see the issue. The object supports UPTO 14 digits. But the PPDB only has 6 digits. So you only need 24 pins to control them.

Bean

w4fej

Bean wrote: »

I see the issue. The object supports UPTO 14 digits. But the PPDB only has 6 digits. So you only need 24 pins to control them.

Bean

Exactly Bean, that threw me also when I tried to use that particular object. It could have been described a bit better in the comment section of the object. Bottom line it works with 24 pins..

Mike B.

Duane Degn

wdfreemanjr ,

I like to use shift registers (74HC595) to drive LED displays. Three pins and three chips will control the 24 pins for you.

You can also plug a TV into your board to use as a display.

Duane