Experimenting w/ TLC5916/17

[MrDEB]

Been trying to get this application schematic working (see bottom of first page using a 555) but my breadboard is a RS item and I have issues with some of the connections sometimes (could be the dang jumper wires) but am in the middle of soldering to a circuit board.
This chip could eliminate the many resistors and the 74373's you have been using??
http://www.ti.com/litv/pdf/slva346
Found this used in this project http://picprojects.org.uk/projects/lc/index.htm
Will let you know how I am progressing but thinking IF it does what it says or I interpret I could cut my parts count on the bike project??
I got the thing assembled just need to test.

[MrDEB]

I got the circuit working and wondering how a 20ma LED can ruin at 69.5ma?
Maybe because its blinking at a 10khz rate?
with two leds in parallel I have 139.2ma draw.
http://www.ti.com/lit/ds/slvs695c/slvs695c.pdf
Maybe a substitute for the 74373's?? and control the current to boot!!

[brad]

That looks like a great chip!

How much did they cost you?

[MrDEB]

Purchased 4 at $1.86 each from Digi-Key.
I discovered from this project http://picprojects.org.uk/projects/lc/index.htm
this chip would save on resistors, 74ls373's and uln2803's
I think it comes in an 8channel and 16 channel?
using as the high side driver TD62783APG(OJS)-ND
Basically the opposite of the uln2803

[bitfogav]

Yeah there just, 16 channel constant current led drivers, you only need one resistor to set the current and you can daisy chain them..

Think I posted the info about this before
viewtopic.php?f=16&t=16&hilit=Constant+current

[brad]

That's right - I think I then went out and bought some! (and then forgot all about them...)

[MrDEB]

Been doing some reading and just about got my experimentation board assembled to "play" with this chip.
While reading I came across application note SLYT225 dealing with dot correction!!!
now this looks interesting for using with bi color LED matrix's. On my 5 x7 matrix the Green draws lss current thus they are not as BRIGHT.
Going to look into this dot correction.
As a side note, using the TLC5926/27(16 channel version)I can lower my parts count even further.
original circuit had 1- 40 pin PIC, 2-ULN2803's, 5 resistors and potential to draw more than 25ma per pin.
now it looks like 1-18pin PIC, 1- TLC5926/27, 1- high side driver, 1 resistor.
would be curious to figure out the amount of pcboard square inches saved not to mention less power needed.

[MrDEB]

WEll kinda got it working but I have a flaw in my code. Pretty sure I am not passing the bits correctly. Only using 5 rows and 5 colums but using this code I am turning on 5 dots in one row then it blinks and ten dots in two rows, blinks fifteen dots in 3 rows until all 5 rows are on and blinking. Havn't had much time to figure it out. Got it "working" last night before going to church. Our KoC council are putting on a fundraising breakfast this morning(its 3:52 am)so I am off to start cooking at 6am.
Just couldn't sleep what with the time change.
My code I tried putting the latch enable etc in same order as the graph in the data sheet application showing timing diagram. Looking at the diagram it has a Dn notation??

Code: Select all

{
*****************************************************************************
*  Name    : UNTITLED.BAS                                                   *
*  Author  : [select VIEW...EDITOR OPTIONS]                                 *
*  Notice  : Copyright (c) 2012 [select VIEW...EDITOR OPTIONS]              *
*          : All Rights Reserved                                            *
*  Date    : 10/26/2012                                                     *
*  Version : 1.0                                                            *
*  Notes   : needs better definition of when pulse train is received                                                               *
*          :                                                                *
*****************************************************************************
}
 Device = 18F2420
Clock = 8
Config MCLRE = Off


'*********************************************************************
'Includes
//Include "InternalOscillator.bas"

Include "utils.bas"
Include "convert.bas"
Dim led1 As PORTC.6    // data
Dim led2 As PORTC.7
dim  Latch_E as portb.0
dim Out_E as  portc.3
dim row1 as portb.3

Dim x As Byte
 const data(5) as byte = (%00000001,%00000011,%00000100,%00001000,%00000000  )

// set ports as outputs
TRISA = %00000000
TRISB = %00000000
TRISC = %00000000       


SetAllDigital
//xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
 //wait until sig = 1 to exicute more code 
  

//xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx 
//needs better definition of when pulse train is received 
// using a very slow 555 to experiment with
// a frequency counter would be better? 
//----------------------------------------------------------


 While 1=1     
   For x = 0 To 7  // time to get sample  // get 100us seconds sample
       
       PORTC.bits(7) = data(x)    // clock  8 pulses clk up
       out_E = 1            // yellow led
       
       latch_e = 0
       PORTC.bits(6) =  1    // sdi in
       DelayMS(100)
       PORTC.bits(7) = 0    //clock dwn
       delayms(100)
      Next
       latch_e = 1
       
       out_E = 0
       PORTC.bits(6) =  0
       row1 = 1  
     delayms(1000)
     row1=0
   Wend

   



   
      
     
  
     
     
     
    
      

[MrDEB]

pic of timing diagram
iIn the Truth table it has Dn??
Am assuming it denotes bits?

timing diagram.png (186.51 KiB) Viewed 22131 times

[MrDEB]

This might help
Portc.3 = output enable
portc.6 = sdi
port c.7 = clk
portb.0 = latch enable

After looking over my code I found two mistakes. Am GOING IN DEEP
BUT man are these LEDs BRIGHT!! but havn't measured the current draw but the ext resistor is 815 ohms(measured)

[brad]

I don't suppose you have a video of what the display looks like running your code?

[brad]

By the way, how did you fundraiser go?

[MrDEB]

I can make a video but I think I found an easier method to program and retrieve the data from parallel to serial and only use one pin for the data (not by using CONST arrays with the bits in the arrays
Found this idea example late last night and constructing the sample today to try it out. I had a similar idea but finding the example substantiates my idea.
The fundraiser yesterday was for MAHONEY HOUSE, a family crisis center here in Salmon. We had a very large crowd as usual for this yearly event, served 150 plates of pancakes, sausage, eggs, coffee, tea, O.J. ALL BY DONATION ONLY!!
Proceeds = $1073.53

[brad]

Well done on the fund raiser!

What was your method for data transfer?

[MrDEB]

If I understand your question correctly, it was suggested to use the shift.bas in swordfish. The data is from the CONST arrays. For the "data" using wireless I am going with the HT12E and HT12D chips.
I tried using a "BIT BANG" approach to shifting the TLC5916 regesters but no luck. bad idea. Even contemplated using SPI but Jon over at DDIY suggested using SHIFT.bas. Hav't got that far yet but will start "hacking" today.