general question - working with the zero and Würth's github examples

I can't help you with Arduino things but I looked at the PlatformIO stuff on the web and found this:

https://docs.platformio.org/en/latest/what-is-platformio.html

I liked the bit that says:

It seems that the gulf between hype and real life is as big as ever. !

Having said that, you can easily enough delve into the Wurth code on Github - it doesn't seem to be well explained which is all too typical of example code.

(Almost all the explanation on the Github is about the tools and wrinkles of compiling the code rather than explaining what really goes on. A bit like giving someone a fish rather than teaching them how to catch their own.)

If you can find the file ICLED_24bit.cpp you can see how it works.

They use the SPI peripheral to output the ICLED data stream, packing two bits into each SPI output byte.

Then they use DMA to output a packet of SPI bytes.

Most people do it the same way (using SPI).

For what its worth (possibly not much) here is some code I hacked together in a hurry a while ago to drive neopixels. It doesn't use DMA although I thought it might, hence the definition of some unused DMA stuff in lines 25 - 28.

//
//       FILE: dctrl_serial.c
//  COPYRIGHT: 2024 MK Electronics Ltd
//
//     AUTHOR: MK
//       DATE: 08/09/2024
//     ORIGIN: New
//
//    PROJECT: Neopixel test on DCTRL
//   HARDWARE: GD32E103C8
// TOOL CHAIN: KEIL
//



#include "dctrl_project.h"
#include "dctrl_main.h"
#include "neopix_neo.h"
#include "dctrl_gpio.h"
#include "dctrl_serial.h"
#include <math.h>

// DEFNITIONS

#define USART_DMA       DMA0
#define RX_DMA_CHAN     4u
#define TX_DMA_CHAN     3u
#define USART0_DA  ((uint32_t)0x40013800u + 0x04u)

#define BIT0    0x08u
#define BIT1    0x0eu

// GLOBAL VARIABLES

uint16_t pix_buff[(N_PIX * 6u) + 2u];
uint16_t pix_buff_size = (N_PIX * 6u) + 2u;
uint16_t pix_buff_idx = 0;
bool gb_pix_tx = false;




void neopix_spi_init(void)
{
    rcu_periph_clock_enable(RCU_SPI1);
    
    SPI_CTL0(SPI1) = 0x081cu;                       // master mode, pol = 0, pha = 0, baud divide  = 8 and SSM and SSI, 16 bit word
    SPI_CTL1(SPI1) = 0x80;                          // transmit buffer empty interrupt
}    

void NVIC_Configuration(void)
{
   
    nvic_priority_group_set(NVIC_PRIGROUP_PRE0_SUB4);   
    nvic_vector_table_set (NVIC_VECTTAB_FLASH,0x0);     // Set the Vector Table base location at 0x08000000       
    nvic_irq_enable(SPI1_IRQn, 7,1);                    // preemption Priority = 7, Sub Priortiy = 1 
    
}

void SPI1_IRQHandler(void)
{
    uint16_t sr;
    sr = SPI_STAT(SPI1);
    if ((sr & 0x02) != 0)
	{
        SPI_DATA(SPI1) = pix_buff[pix_buff_idx++];
        if (pix_buff[pix_buff_idx] == pix_buff_size)
        {
            gb_pix_tx = false;
            pix_buff_idx = 0u;
            SPI_CTL1(SPI1) = 0x0;
        }
    }
}

bool neopix_start(void)   
{
    bool reply = true;
    
    
    if (gb_pix_tx == false)
    {
        
        SPI_CTL0(SPI1) &= ~0x40u;
        SPI_CTL1(SPI1) = 0x80;

        SPI_CTL0(SPI1) |= 0x40;                         // start spi    
        gb_pix_tx = true;
    }
    else
    {
        reply = false;
    }
    
    return reply;
    
}

            
bool write_pix(uint16_t pix, uint8_t green, uint8_t red, uint8_t blue)
{
    bool reply = true;
    uint32_t bin_data = (green << 24) + (red << 16) + (blue << 8u);
    uint16_t pix_idx = pix * 6u;
    uint8_t pix_word;
    uint16_t temp_word;
    uint8_t rgb_bit;
    
    if ((pix >= N_PIX) && (gb_pix_tx == false))
    {
        reply = false;
    }
    else
    {
        for (pix_word = 0; pix_word < 6u; pix_word++)
        {
            temp_word = 0u;
            for(rgb_bit = 0; rgb_bit < 4u; rgb_bit++)
            {
                temp_word <<= 4u;
                temp_word += ((bin_data & 0x80000000u) == 0u) ? BIT0 : BIT1;
                bin_data <<= 1;
            }
            pix_buff[pix_idx++] = temp_word;
        }
    }
    
    return(reply);
}
                
void neo_test(void)
{
    pix_buff[pix_buff_size - 1] = 0;
    pix_buff[pix_buff_size - 2] = 0;
    write_pix(0, 0, 255, 0);
    write_pix(1, 0x0, 0x0, 255);
    
    neopix_start();
    
}

void neo_test2(void)
{
    double x;
    double seed = 17342.4325086579478594365;
    double other_seed = 353.730953869873357895;
    uint16_t step;
    double intpart;
    uint64_t bigint;
    uint8_t col;
    uint8_t rgbs[6];
    
    pix_buff[pix_buff_size - 1] = 0;
    pix_buff[pix_buff_size - 2] = 0;
    
    for(step = 0u; step < 1000; step++)
    {
        x = seed / (other_seed + (double)step);
        x = modf(x, &intpart);
        x *= 2.81e14;
        bigint = x;
        for (col = 0; col < 6; col++)
        {
            rgbs[col] = bigint & 0xff;
            bigint >>= 8;
        }
        write_pix(0, rgbs[0], rgbs[1], rgbs[2]);
        write_pix(1, rgbs[3], rgbs[4], rgbs[5]);
            
        
        neopix_start();
        delay_us(500000);
    }
    
}

The comments in the code are not that helpful - sorry.

MK

thank you! i'll look into your code in the morning. tonight after i got back from class i had a bit of an idea, and i got the build to be successful. i uploaded it to the zero, which was also successful, but the LEDs won't light up. i'll check tomorrow with the scope if there's any activity in the pins. thanks again! sorry about the late reply, busy few days! 

thank you! i'll look into your code in the morning. tonight after i got back from class i had a bit of an idea, and i got the build to be successful. i uploaded it to the zero, which was also successful, but the LEDs won't light up. i'll check tomorrow with the scope if there's any activity in the pins. thanks again! sorry about the late reply, busy few days!