Problem when using PSOC6 DMA to control WS2812b

[Andre_lyl]

Hello, I am doing a project with PSoC 63 BLE pioneer kit and WS2812b LED matrix. And I found alan has posted a tutorial about how to control WS2812 with PSoC 6 DMA.  And I downloaded the code and running the program on my own kit. But it didn't work. I use the oscilloscope to measure the signal from the output port(p0.3), there is no signal.  can someone tell me how to solve this problem? I am now a beginner of PSoC and stuff with hardware, I really don't know how to solve it. I noticed that the PSoC 6 is a 3.3v microcontroller and the WS2812 is a 5V component. Do I need to add a level shifter between them?

The following is the blog and code I use and my hardware connection. Blog: https://iotexpert.com/psoc-6-dma-ws2812-leds/

[AlanH_86]

Here is a non-dma version which works well.

https://github.com/iotexpert/ws2812_led

[BragadeeshV · Accepted solution]

Hi @Andre_lyl ,

1. Did you probe the MOSI pin P13.0 that has the output of the SPI? Can you please let me know how you are controlling P0.3? I do not see in your code where you are controlling P0.3

2. It is recommended to use a level shifter since the voltage levels at  these two interfaces are different.

3.  The project is menu driven using UART terminal. It is required to enable the channel to start the DMA transfer so that you see some output in the MOSI pin. Did you give an input from the UART terminal to trigger the DMA transfer?

[Andre_lyl]

Hi, Thanks for your reply. I think I misunderstand the code, I thought p0.3 is the output of DMA, but it's not. Now I connected the signal line of LED Matrix to the MOSI pin and I found LED Matrix starts to work.😁