/**********************************************************************
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* Copyright: (C)2024 LingYun IoT System Studio
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* Author: GuoWenxue<guowenxue@gmail.com>
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*
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* Description: WS2812B strip lights driver on ISKBoard
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*
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* Reference : https://blog.csdn.net/Lennon8_8/article/details/108980808
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*
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* COMPILER OPTIMIZATION WARNING:
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* This driver uses NOP-based delays for precise WS2812B pulse timing. Keil5
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* Arm Compiler(AC6) default '-O3' optimization breaks this by altering loop
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* assembly and branch structures, causing timing collapse.
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* Fix: Options for Target -> C/C++ (AC6) Set Optimization to -O1.
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* Note: GCC compiler (STM32CubeIDE/VSCode) is NOT affected.
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*
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* ChangeLog:
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* Version Date Author Description
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* V1.0.0 2024.08.29 GuoWenxue Release initial version
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*
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***********************************************************************/
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#include <string.h>
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#include <stdint.h>
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#include "ws2812b.h"
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#include "miscdev.h"
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static color_t g_ColorPanel[WS2812_NUM];
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typedef struct ws_gpio_s
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{
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GPIO_TypeDef *group;
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uint16_t pin;
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} ws_gpio_t;
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/* 使用 ws_gpio 结构体进行 GPIO 操作，便于移植 */
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static ws_gpio_t ws_gpio =
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{
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.group = GPIOC,
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.pin = GPIO_PIN_2,
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};
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#define ws_set_high() (ws_gpio.group->BSRR = ws_gpio.pin)
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#define ws_set_low() (ws_gpio.group->BRR = ws_gpio.pin)
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/* 配置 WS2812B 灯带的 GPIO 口 */
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void ws2812b_init(void)
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{
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GPIO_InitTypeDef GPIO_InitStruct = {0};
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GPIO_InitStruct.Pin = ws_gpio.pin;
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GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
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GPIO_InitStruct.Pull = GPIO_NOPULL;
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GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
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HAL_GPIO_Init(ws_gpio.group, &GPIO_InitStruct);
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ws2812b_reset();
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return ;
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}
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/*
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* 使用内联汇编 NOP 实现纳秒级精确延时 @ 80MHz: 1 NOP = 12.5ns
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*
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* 根据数据手册时序：
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* T0H: 220~380ns (recommend 300ns = 24 cycles)
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* T0L: 580~1000ns (recommend 800ns = 64 cycles)
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* T1H: 580~1600ns (recommend 1100ns = 88 cycles)
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* T1L: 220~420ns (recommend 320ns = 26 cycles)
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* RES: > 280us
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*
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* 实际测试建议：
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* - 考虑 GPIO 操作本身耗时约 2-3 个时钟周期
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* - 考虑函数调用、判断等开销
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* - 以下数值已预留开销，可根据实测微调 ±2~4 个 NOP
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*/
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/* T0H: 300ns ≈ 24 cycles
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* 减去 GPIO 和判断开销约 6 cycles，使用 18 NOPs
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*/
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#define delay_T0H() __ASM volatile( \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t" \
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)
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/* T0L: 800ns ≈ 64 cycles
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* 减去开销约 6 cycles，使用 58 NOPs
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*/
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#define delay_T0L() __ASM volatile( \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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)
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/* T1H: 1100ns ≈ 88 cycles
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* 减去开销约 6 cycles，使用 82 NOPs
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*/
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#define delay_T1H() __ASM volatile( \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t" \
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)
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/* T1L: 320ns ≈ 26 cycles
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* 减去开销约 6 cycles，使用 20 NOPs
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*/
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#define delay_T1L() __ASM volatile( \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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"NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t NOP\n\t" \
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)
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static inline void ws2812b_WriteByte(uint8_t byte)
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{
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int i;
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for(i=0; i<8; i++)
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{
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if(byte & 0x80)
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{
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/* Sequence Send 1:
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*
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* +--------------+ +
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* |<- T1H ->|<- T1L ->|
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* | +---------+
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*/
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ws_set_high();
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delay_T1H();
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ws_set_low();
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delay_T1L();
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}
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else
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{
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/* Sequence Send 0:
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*
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* +---------+ +
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* |<- T0H ->|<- T0L ->|
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* | +--------------+
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*/
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ws_set_high();
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delay_T0H();
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ws_set_low();
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delay_T0L();
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}
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byte <<= 1;
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}
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return ;
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}
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void ws2812b_reset(void)
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{
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/* RES: low voltage time > 280us */
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ws_set_low();
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udelay(300);
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memset(g_ColorPanel, 0, sizeof(g_ColorPanel));
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return ;
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}
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static inline void ws2812b_SendColor(color_t color)
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{
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ws2812b_WriteByte(color.pixel.green);
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ws2812b_WriteByte(color.pixel.red);
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ws2812b_WriteByte(color.pixel.blue);
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return ;
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}
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static inline void ws2812b_Refresh(void)
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{
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int i;
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uint32_t primask;
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/* 关闭中断保证时序准确 */
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primask = __get_PRIMASK();
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__disable_irq();
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for(i=0; i<WS2812_NUM; i++)
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{
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ws2812b_SendColor(g_ColorPanel[i]);
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}
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/* 恢复中断状态 */
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__set_PRIMASK(primask);
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return ;
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}
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static inline int ws2812b_SetPixel(int which, color_t color)
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{
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if( which<0 || which>=WS2812_NUM )
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return -1;
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g_ColorPanel[which].pixel.red = color.pixel.red;
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g_ColorPanel[which].pixel.green = color.pixel.green;
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g_ColorPanel[which].pixel.blue = color.pixel.blue;
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return 0;
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}
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int ws2812b_turn(int which, color_t color)
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{
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if( which<0 || which>=WS2812_NUM )
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return -1;
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ws2812b_SetPixel(which, color);
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ws2812b_Refresh();
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return 0;
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}
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void ws2812b_blink(void)
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{
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int c, i;
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color_t colors[4] = {[0].data=PIXEL_B, [1].data=PIXEL_R, [2].data=PIXEL_G, [3].data=PIXEL_W};
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color_t color_off = {.data = PIXEL_OFF};
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for(c=0; c<4; c++) /* color */
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{
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for(i=0; i<WS2812_NUM; i++)
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{
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ws2812b_turn(i, colors[c]);
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mdelay(300);
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ws2812b_turn(i, color_off);
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mdelay(300);
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}
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}
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}
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