New LED driver for PPDB Now Available

tonyp12 · 2011-01-30 18:56

http://www.parallax.com/Store/Microcontrollers/PropellerDevelopmentBoards/tabid/514/CategoryID/73/List/0/SortField/0/Level/a/ProductID/515/Default.aspx

The 17 segment LEDs is not very often used to it's high amount of pins it uses.

Solution: a daughter board that is only using 3 prop pins, be powered with 3.3v or 5v.

Using three 74VHC595 and three dual-npn to sink the digits common cathodes.

To get better load balance,
I decided to that each 595 sources 6 led anodes
and 2 pins goes to the transistors.

I'm waiting to hear from parallax about the spacing of the gap between upper/lower pin cluster.
(I don't own a ppdb)
Hopefully it's 0.1" so you could use it on any bread board and not just the ppdb.

Any inputs before I send it away for order?

kuroneko · 2011-01-30 19:06

tonyp12 wrote: »

I'm waiting to hear from parallax about the spacing of the gap between upper/lower pin cluster.

If by that you mean the spacing between the 2x6 and 2x17 block, they are both aligned to 0.1" (there is effectively one usused pin between them).

WBA Consulting · 2011-01-30 21:44

That's pretty slick. I would probably finally use those 7 segment LEDs that are collecting dust on my PPDB. I typically just use TV out for simplicity of setup, but this would change that and enable me to use the PPDB by itself (no TV/VGA monitor/serial LCD/etc).

Jim Fouch · 2011-01-31 07:18

Mark me down for two.

Duane Degn · 2011-01-31 09:28

The breadboard is 0.06" higher than the tops of the headers on the board. You'll want to make sure pins are long enough to reach the headers across this gap.

As kuroneko mentioned, the first pin (left most) on the second display header is 0.2" from the last pin (far right) on the first display header. Making the headers spaced so one pin would fit between the two headers.

The last pin (P0) on the header of Propeller pins is about 0.15" from the first pin the first display header. Since these headers are so close together, I'm afaid your board might block part of the P0 header.

This is would be a useful item.

Is the price for the board include the ICs?

tonyp12 · 2011-01-31 10:23

So it's confirmed that the space is just one "missing" pin, good.

I did plan to move the pin headers closer to the upper limit, so not to block P0

Yes, the price includes ICs and also a simple software driver.

SEL · 2011-01-31 11:57

I would very much like to purchase this board. Please let me know when it is available>

zappman · 2011-01-31 14:47

What a great idea!
Will the board come assembled?
I know you said it comes with the parts.
I don't see any caps across the power power pins of the ICs, are there any?
This would be a great addition to my PPDB, so far I have never used the displays, due to lack of drivers.

tonyp12 · 2011-01-31 18:26

Is decouping really neassary?, but in any case I added three
0.1uF decoupling (a.k.a by-pass) capacitors. that's gray 0805s in picture.

Also moved up layout a little to make sure P0 would not be blocked.

Yes it will come completely assembled.

I will probably use NXP's AHC595 when soic version of it is in stock.

Duane Degn · 2011-01-31 19:27

I'll want at least one.

I agree that the caps are a good idea.

RobotWorkshop · 2011-02-09 13:40

Did you have any of these boards made yet? I'd like to get one and I know of at least one other person (that doesn't frequent the forums often) that would want one too.

Robert

tonyp12 · 2011-02-17 13:28

I got one made, everything is working as expected.
I will have 20 units ready in about a week.

It can control 102 LEDs with it's 16% duty cycle.

I'm using 2K resistors for the NPN transistor base
specs shows:
hFE DC current gain VCE = 5 V; IC = 2 mA.......typical 300
VBEsat base-emitter saturation voltage IC = 100 mA; IB = 5 mA
I guess 1K would be complete saturation at 5v, but 2K would be fine even for 3.3v?
http://www.nxp.com/documents/data_sheet/BC846DS.pdf

mov       asm_cnt,bit_test    'load the value that only have bit 24 set to 1.
         
:loop2        test      serial,asm_cnt wz   'is this bit a 1?
              muxnz     outa,#4             'the answer is in z, and turn pin4(serial) based on this.
              or        outa,#1             'turn pin0 on  (clock) 
              andn      outa,#1             'turn pin0 off (clock)
              sar       asm_cnt,#1 wz       'shift right
        if_nz jmp       #:loop2             'if not zero, jmp 
              
              or        outa,#2             'turn pin1 on  (latch) 
              andn      outa,#2             'turn pin1 off (latch)   

serial        long      %00000000_11111100_11111100_11111110 'the two lower bits in each byte controls the 6 npn transistors
bit_test      long      %1<<24

Invent-O-Doc · 2011-02-17 14:53

So Im not the only one. I found the old PDB for stamps/SX 7-segs much more useful. They just aren't worth wiring up on the PPDB unless I add jumpers to make them 7-segs. Even then. I'm always going to video or TTL out.

tonyp12 · 2011-02-28 15:56

I have 12 units ready for sale, introduction priced at $16.00 +$3.50 shipping per order ($2 more for international shipping)
Limit 2 per person
(edit: they are fully assembled)
payment by paypal.com

Video showing mutiplexing in slowmotion
More units will be made.

doggiedoc · 2011-02-28 16:52

Are you selling them as kits or assembled?

Paul

tonyp12 · 2011-02-28 17:45

fully assembled

doggiedoc · 2011-02-28 18:50

I'll take 2. Paypal sent!

Paul

RobotWorkshop · 2011-02-28 19:24

I want one! Please check your messages and I should be covered.

Thank You!

Robert

zappman · 2011-02-28 19:31

Paypal sent for 2 units

Duane Degn · 2011-02-28 19:48

I also just sent you $ for two.

Thanks,

Duane

zappman · 2011-03-05 09:45

Tony,

I just received (3/5/2011) my two "17 Segment LED Driver Boards for the PPDB"

.
I tried it with the test program Tony e-mailed and it works great.

Thanks,
zappman

tonyp12 · 2011-03-07 15:55

I just created the fonts 0-9 and A-Z
I post it here if someone else wants them
My full spin driver for the 17seg Led driver should be avilable soon.

font          long      A1+A2+B+C+D1+D2+E+F+J+M         '0
              long      B+C                             '1
              long      A1+A2+B+D1+D2+E+G1+G2           '2
              long      A1+A2+B+C+D1+D2+G2              '3
              long      B+C+F+G1+G2                     '4
              long      A1+A2+D1+D2+F+G1+K              '5
              long      A1+A2+C+D1+D2+E+F+G1+G2         '6
              long      A1+A2+B+C                       '7
              long      A1+A2+B+C+D1+D2+E+F+G1+G2       '8
              long      A1+A2+B+C+D1+D2+F+G1+G2         '9
              long      0,0,0,0,0,0,0                   'unused
              long      A1+A2+B+C+E+F+G1+G2             'A
              long      A1+A2+B+C+D1+D2+G2+I+L          'B
              long      A1+A2+D1+D2+E+F                 'C
              long      A1+A2+B+C+D1+D2+I+L             'D
              long      A1+A2+D1+D2+E+F+G1+G2           'E
              long      A1+A2+E+F+G1                    'F
              long      A1+A2+C+D1+D2+E+F+G2            'G
              long      B+C+E+F+G1+G2                   'H
              long      I+L                             'I
              long      B+C+D1+D2+E                     'J
              long      E+F+G1+J+K                      'K
              long      D1+D2+E+F                       'L
              long      B+C+E+F+H+J                     'M
              long      B+C+E+F+H+K                     'N
              long      A1+A2+B+C+D1+D2+E+F             'O
              long      A1+A2+B+E+F+G1+G2               'P
              long      A1+A2+B+C+D1+D2+E+F+K           'Q
              long      A1+A2+B+E+F+G1+G2+K             'R
              long      A1+A2+C+D1+D2+F+G1+G2           'S
              long      A1+A2+I+L                       'T
              long      B+C+D1+D2+E+F                   'U
              long      E+F+J+M                         'V
              long      B+C+E+F+K+M                     'W
              long      H+J+K+M                         'X
              long      H+J+L                           'Y
              long      A1+A2+D1+D2+J+M                 'Z

RobotWorkshop · 2011-03-07 16:39

I just received the one that I ordered and I must say it looks nice! After I get the kids to sleep I'm going to try it out.

Robert

SSteve · 2011-03-08 09:59

I just ordered one

doggiedoc · 2011-03-08 13:49

zappman wrote: »

Tony,

I just received (3/5/2011) my two "17 Segment LED Driver Boards for the PPDB" .
I tried it with the test program Tony e-mailed and it works great.

Thanks,
zappman

Already! Dang! Mine hasn't arrived yet.

doggiedoc · 2011-03-10 05:08

Got them! Look forward to playing with them tonight!!

Thanks Tony!

Paul

Duane Degn · 2011-03-10 07:38

I received mine yesterday. Thanks Tony.

I haven't played with mine yet.

I think I'm going to switch the two and three pin headers for female headers. I'm thinking with female headers, I can use normal hookup wire to make the necessary connections.

I'm curious if any of you prefer the male headers and why?

Somewhere I should have an object that uses both uppercase letters and lowercase letters for these 16-segment LEDs. I found the lowercase example somewhere on the internet.

When I find it, I'll share it here.

Oldbitcollector (Jeff) · 2011-03-10 07:46

Is it possible to order one of these without the male hookup headers installed?

OBC

tonyp12 · 2011-03-10 09:11

I guess I thought ever one had a few femal to male jumpers around.
http://www.schmartboard.com/index.asp?page=products_jch&id=127

I'm sold out now, Next batch I make I will go with female headers.

Oldbitcollector (Jeff) · 2011-03-10 09:35

Please put me down for one, possibly two when you get the next batch in.

OBC

RobotWorkshop · 2011-03-10 11:51

Duane Degn wrote: »

I think I'm going to switch the two and three pin headers for female headers. I'm thinking with female headers, I can use normal hookup wire to make the necessary connections.

I'm curious if any of you prefer the male headers and why?

For this application the female connectors like the ones used on the development board make more sense for this particuar application. I think I have some and may switch those out. For anyone keeping the male headers you may want to switch those with straight ones that stick up. The original ones that lay down may interfere with projects on the proto area.

Other than that it works great and now I can finally use those nice displays! I think I'm just going to leave it on the board all the time now.

Robert

New LED driver for PPDB Now Available

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