CH5xx WS2812B by PWM/TMR/DMA/UART example - #887
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…. Added an example of using UART to drive WS2812Bs on CH584/5.
…32fun into ch57x-ws2812b-pwm
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@mattshepcar why not just use the code in the WS2812B driver in extralibs? https://github.com/cnlohr/ch32fun/blob/master/extralibs/ws2812b_dma_spi_led_driver.h#L243-L273 it works on the CH5xx |
Fixed typo and clarified explanation of UART lookup table.
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Mainly because I don't want to or can't use the SPI pins. This also gives an example of how to set up PWM/TMR DMAs which could be used for things other than driving WS2812Bs. |
| #define TMR_PA9 1 | ||
| // the PWM buffers start and end with zero entry (duty cycle of 0 = output off). | ||
| // I'm not sure why the start one is needed but you get flickering without it. | ||
| uint16_t __attribute__((aligned(4))) WS2812B_PWM123_LedBuffer[(NR_LEDS * 24 + 2) * 3] = {0}; |
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Can you add a comment here explaining why the alignment? (I.e. because these are the raw buffers that are sent out via DMA)
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| static const uint8_t WS2812B_UART_LUT[8] = | ||
| { | ||
| ~0b0100100, // 9 bits are used to encode 3 bits of WS2812B data. |
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You don't need to change this! But, specifying ~ in a LUT is not normally a natural way to express this, instead, you would normally write out the inverted bitstream in the LUT. This is to make debugging easier.
| ~0b0101101, | ||
| ~0b1101101, | ||
| }; | ||
| void WS2812B_UART0_Send(const uint32_t* ledData, int numLeds) |
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Can you write a blirb about these functions and what they do, and whether the ledData pointer is used as the DMA pointer, and/or if the data is made available upon completion or after completion.
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| } | ||
| #ifdef CH57x | ||
| void WS2812B_PWM_Init(int channel) |
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Normally, you would make these zero indexed, even though it would disagree with the datasheet. So because you are matching the datasheet, can you change it around so that makes it clear that it's pwm_channel_1_indexed
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this is really close, do you mind fixing the things I outlined? they're mostly documentation. |
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@mattshepcar up for addressing the comments? |
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An example of some other ways to drive those fancy addressable LEDs on CH5xx MCUs for when you don't want to use the SPI pins or you need even more LEDs.