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Controlling TLC5940 with MSP430G2553 doesn't work


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I did this with the 2553 installed in a launchpad with 5940 in breadboard.   Do you get them to light at all? I have the 5940 with all leds burning bright right now using your code. I edited the cod

Same results as Kyle. Added remaining LEDs later on just to make sure LP's LDO is not an issue here and all LEDs light up. My RIREF is 2k2, so the total current is just under 320mA.  

Reset on the 2553, pin 10 in the second schematic, which has nothing connected to it but needs a pull-up resistor to function.

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It's hard to tell where the problem would lie.

 

Have you tried just copying and pasting the working example code from here and running it straight? No modifications?

 

That's where I would start. If that works, something needs changed in your program. If that doesn't work there is something wrong with the hardware and I would check that the MCU is able to even blink an led.

 

viewtopic.php?f=10&t=1700

 

I know that code works so if that doesn't run, something is askew.

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I recall already trying it but I'll try it tomorrow again..it didn't work the first time though.

 

The MSP430 and the LEDs are working. Already built a traffic light (switching between red, yellow and green leds with programmed time interval) with both parts.

 

Maybe my TLC5940 is broken but I already replaced it with another (got 3 of them as samples from TI). :((

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I did this with the 2553 installed in a launchpad with 5940 in breadboard.

 

Do you get them to light at all? I have the 5940 with all leds burning bright right now using your code. I edited the code and it does change the way the leds behave. Your GSCLK is very slow however as the leds that don't have full brightness blink instead of dimming. If you add "BCSCTL1 = CALBC1_16MHZ;" under your watchdog code it will dim though.

 

Your code keeps the processor very busy. I would recommend using a timer to output your clock signal while the MSP goes about other business. Doesn't matter if you pre-program a routine but if you want the MSP to do anything else while running this chip there is no time for it.

 

Do you have bypass capacitors on the breadboard?

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I would recommend using a timer to output your clock signal while the MSP goes about other business. Doesn't matter if you pre-program a routine but if you want the MSP to do anything else while running this chip there is no time for it.

It's just an initial test programmed like described in the programming flowchart by TI

 

Do you have bypass capacitors on the breadboard?

if you mean decoupling capacitors, then yes as you can see in the schematics.

 

It looks like its a hardware / wiring fault then :/

 

Have you guys tried it with the MSP430 directly on the Breadboard (not on the launchpad) ?

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Ah, yes! The Reset Pin is connected to the Launchpad for programming.

 

Your 2553 is on the breadboard, TEST, RST, and GND are connected to LP.

Is your breadboard's Vcc connected to LP's Vcc?

Are you disconnecting LP after programming?

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Is your breadboard's Vcc connected to LP's Vcc?

Well, its like that

MSP and TLC are on the breadboard.

 

TEST, RST, GND and Vcc of the MSP are connected to the LP.

TLC's Vcc and GND are also taken from LP.

Breadboards Vcc aka Vled is only for the leds.

 

Are you disconnecting LP after programming?

No, I'm not. Is it worth a try?

Is there anything I need to do instead then like resistors on any point?

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Still works off the LP. I would check every wire meticulously.

 

post-12850-135135556907_thumb.jpg

 

You can even see the dimmer running blue led on the right so I know the program is running. (with 16MHz clock)

 

TLC - MSP wire connections on my breadboard.

18 - 2

19 - 12

23 - 7

24 - 13

25 - 6

26 - 4

27 - 11

 

Launchpad to MSP is only VCC, GND, TEST, RST. I even reloaded the program to make sure that it will program ok like this.

 

I know it sounds dumb, but also check your LED polarity. I spent a few minutes scratching my head and it was backwards installed leds.

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