ARM WS2812 SPI config (baudrate and circular buffer) (#12216)
* initial commit * include circular buffer command * add endif * circular buffer mode * remove untrue comment * revamp and add documentation * do not allow WS2812_SPI_SYNC & CIRCULAR_BUFFER
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2 changed files with 59 additions and 4 deletions
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@ -77,6 +77,25 @@ Configure the hardware via your config.h:
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You must also turn on the SPI feature in your halconf.h and mcuconf.h
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#### Circular Buffer Mode
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Some boards may flicker while in the normal buffer mode. To fix this issue, circular buffer mode may be used to rectify the issue.
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By default, the circular buffer mode is disabled.
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To enable this alternative buffer mode, place this into your `config.h` file:
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```c
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#define WS2812_SPI_USE_CIRCULAR_BUFFER
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```
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#### Setting baudrate with divisor
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To adjust the baudrate at which the SPI peripheral is configured, users will need to derive the target baudrate from the clock tree provided by STM32CubeMX.
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Only divisors of 2, 4, 8, 16, 32, 64, 128 and 256 are supported by hardware.
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|Define |Default|Description |
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|--------------------|-------|-------------------------------------|
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|`WS2812_SPI_DIVISOR`|`16` |SPI source clock peripheral divisor |
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#### Testing Notes
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While not an exhaustive list, the following table provides the scenarios that have been partially validated:
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@ -32,6 +32,37 @@
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# endif
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#endif
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// Define SPI config speed
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// baudrate should target 3.2MHz
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// F072 fpclk = 48MHz
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// 48/16 = 3Mhz
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#if WS2812_SPI_DIVISOR == 2
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# define WS2812_SPI_DIVISOR (0)
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#elif WS2812_SPI_DIVISOR == 4
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# define WS2812_SPI_DIVISOR (SPI_CR1_BR_0)
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#elif WS2812_SPI_DIVISOR == 8
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# define WS2812_SPI_DIVISOR (SPI_CR1_BR_1)
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#elif WS2812_SPI_DIVISOR == 16 //same as default
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# define WS2812_SPI_DIVISOR (SPI_CR1_BR_1 | SPI_CR1_BR_0)
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#elif WS2812_SPI_DIVISOR == 32
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# define WS2812_SPI_DIVISOR (SPI_CR1_BR_2)
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#elif WS2812_SPI_DIVISOR == 64
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# define WS2812_SPI_DIVISOR (SPI_CR1_BR_2 | SPI_CR1_BR_0)
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#elif WS2812_SPI_DIVISOR == 128
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# define WS2812_SPI_DIVISOR (SPI_CR1_BR_2 | SPI_CR1_BR_1)
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#elif WS2812_SPI_DIVISOR == 256
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# define WS2812_SPI_DIVISOR (SPI_CR1_BR_2 | SPI_CR1_BR_1 | SPI_CR1_BR_0)
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#else
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# define WS2812_SPI_DIVISOR (SPI_CR1_BR_1 | SPI_CR1_BR_0) //default
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#endif
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// Use SPI circular buffer
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#ifdef WS2812_SPI_USE_CIRCULAR_BUFFER
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# define WS2812_SPI_BUFFER_MODE 1 //circular buffer
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#else
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# define WS2812_SPI_BUFFER_MODE 0 //normal buffer
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#endif
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#define BYTES_FOR_LED_BYTE 4
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#define NB_COLORS 3
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#define BYTES_FOR_LED (BYTES_FOR_LED_BYTE * NB_COLORS)
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@ -82,13 +113,16 @@ void ws2812_init(void) {
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// TODO: more dynamic baudrate
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static const SPIConfig spicfg = {
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0, NULL, PAL_PORT(RGB_DI_PIN), PAL_PAD(RGB_DI_PIN),
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SPI_CR1_BR_1 | SPI_CR1_BR_0 // baudrate : fpclk / 8 => 1tick is 0.32us (2.25 MHz)
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WS2812_SPI_BUFFER_MODE, NULL, PAL_PORT(RGB_DI_PIN), PAL_PAD(RGB_DI_PIN),
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WS2812_SPI_DIVISOR
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};
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spiAcquireBus(&WS2812_SPI); /* Acquire ownership of the bus. */
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spiStart(&WS2812_SPI, &spicfg); /* Setup transfer parameters. */
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spiSelect(&WS2812_SPI); /* Slave Select assertion. */
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#ifdef WS2812_SPI_USE_CIRCULAR_BUFFER
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spiStartSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
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#endif
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}
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void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) {
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@ -104,9 +138,11 @@ void ws2812_setleds(LED_TYPE* ledarray, uint16_t leds) {
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// Send async - each led takes ~0.03ms, 50 leds ~1.5ms, animations flushing faster than send will cause issues.
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// Instead spiSend can be used to send synchronously (or the thread logic can be added back).
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#ifndef WS2812_SPI_USE_CIRCULAR_BUFFER
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# ifdef WS2812_SPI_SYNC
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spiSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
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# else
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spiStartSend(&WS2812_SPI, sizeof(txbuf) / sizeof(txbuf[0]), txbuf);
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# endif
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#endif
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}
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