RobG 1,892 Posted August 1, 2014 Share Posted August 1, 2014 TLC5940 driver for Tiva / Stellaris. Uses 2 Timers, SSI, and DMA. SPI runs @ 20MHz, GSCLK @ 8MHz, update occurs every ~0.5ms Up to 16 TLC5940s can be daisy chained (in theory, I tested only 2.) main.cstartup_ccs.c L.R.A 1 Quote Link to post Share on other sites
L.R.A 78 Posted August 3, 2014 Share Posted August 3, 2014 can i ask wich is the VCC for the TLC5940? at 3.3V i see flickering problems. Quote Link to post Share on other sites
RobG 1,892 Posted August 3, 2014 Author Share Posted August 3, 2014 I use 3.3V to power Vcc and LEDs. Quote Link to post Share on other sites
pinstruck 0 Posted March 5, 2015 Share Posted March 5, 2015 Hi there, thank you for the code. I'm still trying to learn SSI on the Tiva (I'm a beginner overall). My main question is without the boosterpack in the video, how exactly do you wire up the Tiva to the TLC5940? (I guess more specifically, does PB4 --> SCLK, PB7 --> SIN? If you know where I could find a schematic of the Tiva + the driver that would be awesome) Also what is the PWM timer used for? Thank you. Quote Link to post Share on other sites
RobG 1,892 Posted March 8, 2015 Author Share Posted March 8, 2015 You can find schematic right here. As for the PWM Timer... can't remember why it is there, but I believe I was testing something else and forgot to remove it Quote Link to post Share on other sites
pinstruck 0 Posted March 8, 2015 Share Posted March 8, 2015 Thanks for the schematic, I just tried it out but nothing is lighting up. Where in the code are you clocking/pulsing GSCLK? From the schematic, it looks like P1.4 from the MSP430 maps to PE5 on the Tiva/Stellaris for GSCLK, but that port is not mentioned anywhere in the code. I think that might be the reason why it is not working for me, I'm not supplying the GSCLK signal. Do you have happen to have the code for that? Also I have VCC as 3.3V, with 2.2kOhm resistor on IREF to GND. Thanks again. Quote Link to post Share on other sites
RobG 1,892 Posted March 9, 2015 Author Share Posted March 9, 2015 GSCLK is on PB2. If I remember correctly, I had to short PE5 to PB2 (green wire on the video.) My BP was designed for MSP430G LP, not Tiva. Quote Link to post Share on other sites
pinstruck 0 Posted March 25, 2015 Share Posted March 25, 2015 Real life took over so I couldn't really work on my problem until now. I have tried connecting PB2 to GSCLK but that doesn't work either. Can you please verify that I have wired everything correctly? (Just in case there were other pins you shorted) SIN --> PB7 SCLK --> PB4 GSCLK --> PB2* BLANK --> PA2 XLAT --> PA3 DCPRG --> PA6 VPRG --> PA4 PB2 (Timer3) is configured to capture an incoming positive edge and count. What is the source for that? How would this configuration make it a GSCLK? I was assuming that Timer1, the PWM (PB5), generates the GSCLK and then Timer3 counts its positive edges until it reaches a complete GS cycle. Sorry for the amount of questions. This is quite a learning process for me. Quote Link to post Share on other sites
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