next topic »

[Reply #210 on:]

@bensaddiction: Very weird.  I don't have a Mac to test on, but can anyone else reproduce this?  Try reinstalling Arduino and then the library.

[Reply #211 on:]

Hi, would anyone know what the maximum amount of tlc5940's that you can daisy chain is?
I'd like to go upto 68 or 12, but read elsewhere that +10 is problematic?
Thanks!

[Reply #212 on:]

I've just finished a project with 12 daisy-chained TLC's. I'll put the project online next week. In my case I had each TLC on a separate board. The 12 boards were connected with 11x 20 cm ribbon cable. This gave me some problems with the signal after the 10th board. Because the boards go in a circle, instead of letting the signal travel from the source to the 12th (and back) I was able to split it so I had 0 - 5 and 6 - 11 for all the signals except for SOUT - SIN. That worked ok for me. But I don't think you'll have this problem when you put them all on one board.

[Reply #213 on:]

Where did you get the TLC's? Digikey is backordered until Sept. 14 and I can't find any elsewhere.

Can't wait until you put it online.

[Reply #214 on:]

I got them (5940pwp (smd)) from rsonline.nl.
You can only order there as a company (b2b).

[Reply #215 on:]

Thanks Chronoless, 12 sounds great.
Would you think there will be issues to control 6 arduinos with each 11 TLC5940's on them?

[Reply #216 on:]

When your plan is to control the 6 arduinos through usb than that shouldn't be a problem. But make sure that the configured baudrate is sufficient for your application. But that all depends on the resolution mode (256 (8bit) or 4096 (12bit)) and desired refresh rate.

[Reply #217 on:]

Thanks!

[Reply #218 on:]

has anyone used the tlc5940 with i2c at the same time.  im trying to and getting corrupt data when receiving.  Serial works just fine at speeds of 115200 but i2c does not work.

[Reply #219 on:]

I'm having some annoying probs here. I've connected the 5940 to my arduino NANO according to the schematic, triple-checked everything, but the leds still won't light. The problem seems to be voltage on the outputs. My multimeter reads about 0.2 V when i'm pumping 4000 on the channels. When alternating (slow blinking) the result is the expected (0V, 0.2V, 0V, 0.2V etc).
My usb supply voltage is 4.5V, could that have anything to do with it?

[Reply #220 on:]

the tlc does not source current it sinks it

so the setup needs to be

+--- LED --- TLCinput
also be sure your using the correct resistor value

[Reply #221 on:]

Yeah, thanks, just found out myself. Apparently I hadn't tripled checked the schematic thoroughly enough.   Feel as stupid as can be.

[Reply #222 on:]

is it possible to turn off a pin so that it is used as GND for a LED?

[Reply #223 on:]

just assign the value of 4095 to the correct pin.
this should result in the led being constantly on.

[Reply #224 on:]

its not about constantly turning on a led but rather using a pin of the TLC as GND for multiplexing stuff...