LED 控制器

支持的芯片[ RTL8721Dx ][ RTL8720E ][ RTL8710E ][ RTL8726E ][ RTL8713E ][ RTL8730E ]

概述

LEDC（LED 控制器）是一种高效的嵌入式解决方案，既支持智能 LED 灯具（如 WS2812B）的控制，也能兼容 DSHOT 协议以驱动无刷电机。

功能特性

可配置的数据传输脉冲时间和非数据周期
可配置的 RGB888 显示模式和 LED 刷新时间
最大支持 8192 笔数据序列
最大支持 1024 个 LED
支持 DMA 传输

工作原理

逻辑 0/1 编码及配置指南

逻辑“0”和“1”编码

逻辑“0”（简称“码 0”）和逻辑“1”（简称“码 1”）由高低电平组成，如图所示。

输入码型时序

逻辑电平时序

各设备中，码 0 和码 1 的高低电平持续时间有所不同。

以 WS2812B-2020 智能 LED 为例：

code0_code1_timing
码	描述	时间范围	单位
T0H	码0，高电平时间	220 ~ 380	ns
T0L	码0，低电平时间	580 ~ 1000	ns
T1H	码1，高电平时间	580 ~ 1000	ns
T1L	码1，低电平时间	220 ~ 420	ns
RESET	帧复位，低电平时间	> 280	μs

则编码总时间：

码 0：800ns ~ 1380ns
码 1：800ns ~ 1420ns

编码时间配置

通过调节寄存器中的 TxH_CNT 和 TxL_CNT 参数，可以灵活设置码 0，码 1 的高低电平持续的时钟周期数目。
- x：指 0 或 1
- 计数时钟：XTAL40MHz

数据传输时序

LED 通信模式

以 WS2812B LED 为例，其使用单路非归零（NRZ）通信协议，采用级联方式进行数据传输：

上电复位：LED 上电后，通过 DI 端口从控制器接收数据。首颗 LED 将采集前 24 位数据并锁存。
数据传递：剩余的数据通过内部整形电路从 DO 端口传输到下一颗 LED。
信号递减：每经过一颗 LED，信号中会减少 24 位数据。

LEDC 传输时序

LEDC 发送给首个 LED 的数据时序如下：

LEDC 数据传输时序

复位信号 ：可配置周期，用于刷新 LED。

间隔调整 ：

支持在相邻像素间插入低电平间隔

支持在相邻帧间插入低电平间隔

LED 数量

支持的 LED 数量计算公式为：

LED_NUM = (1 / LED refresh rate (frame/s) - 280 μs) / ((logical 0 or 1 coding time) * 24)

以表 code0_code1_timing 中码 0 和码 1 的时序为例，计算出支持的 LED 数量：

当 LED 的刷新率为 30 帧/秒时，支持的 LED 数量为 681 ~ 1023 个。
当 LED 的刷新率为 60 帧/秒时，支持的 LED 数量为 337 ~ 853 个。

应用示例

raw_ledc_ws2812 展示了如何使用 LEDC 模块来配置和控制多个 LED 灯珠。

备注

要了解示例支持的芯片，请查看示例路径下的 README.md 文件。

Raw API

LEDC Exported Types

struct LEDC_InitTypeDef

LEDC Init Structure Definition.

Public Members

u32 led_count: Number of external LED lamps connected. This parameter can be a value of LEDC LED Number.

u32 data_length: Total transfer data length in 32-bit units. This parameter can be a value of LEDC Data Length.

u32 t1h_ns: Logical "1" high level cycle count.

u32 t1l_ns: Logical "1" low level cycle count.

u32 t0h_ns: Logical "0" high level cycle count.

u32 t0l_ns: Logical "0" low level cycle count.

u32 reset_ns: LED reset signal cycle count N. This parameter can be a value of LEDC Reset Count.

u32 wait_data_time_ns: FIFO data wait timeout cycle count N. This parameter can be a value of LEDC Wait Data Time Count.

u32 wait_time0_en: Enable or disable wait time0 insertion between two LED data packets. This parameter can be: ENABLE or DISABLE.

u32 wait_time1_en: Enable or disable wait time1 insertion between two LED frame data. This parameter can be: ENABLE or DISABLE.

u32 wait_time0_ns: Wait time0 between two LED data packets, cycle count N. This parameter can be a value of LEDC Wait Time0 Count.

u32 wait_time1_ns: Wait time1 between two LED frame data, cycle count N. This parameter can be a value of LEDC Wait Time1 Count.

u32 output_RGB_mode: RGB byte output order. This parameter can be a value of LEDC RGB Mode.

u32 ledc_polarity: Output signal idle level. This parameter can be a value of LEDC Idle Level.

u32 ledc_trans_mode: Data transfer mode (CPU or DMA). This parameter can be a value of LEDC Transfer Mode.

u32 ledc_fifo_level: FIFO trigger level threshold (0 to 31). A DMA or CPU request is generated when the remaining FIFO space exceeds this value. This parameter can be a value of LEDC FIFO Level.

LEDC Exported Constants

LEDC Data Length

/* Maximum LEDC transfer data length (8192 entries). */
#define LEDC_MAX_DATA_LENGTH (0x2000)

/* Checks if the data length parameter is within valid range. */
#define IS_LEDC_DATA_LENGTH ((LENGTH > 0) && ((LENGTH) <= LEDC_MAX_DATA_LENGTH))

LEDC FIFO Level

/* LEDC internal FIFO total depth (32 entries). */
#define LEDC_FIFO_DEPTH (32)

/* Default LEDC FIFO trigger level for DMA/CPU requests. */
#define LEDC_DEFAULT_FIFO_TRIG_LEVEL (15)

LEDC Idle Level

/* LEDC output idle level is low. */
#define LEDC_IDLE_POLARITY_LOW (0)

/* LEDC output idle level is high. */
#define LEDC_IDLE_POLARITY_HIGH (1)

LEDC Input Order

/* LEDC input data bit order: LSB first. */
#define LEDC_INPUT_LSB (0)

/* LEDC input data bit order: MSB first. */
#define LEDC_INPUT_MSB (1)

/* Checks if the input bit order parameter is valid. */
#define IS_LEDC_INPUT_ORDER ((ORDER) == LEDC_INPUT_LSB || \
    (ORDER) == LEDC_INPUT_MSB)

LEDC Interrupt

/* Bitmask for all LEDC interrupt sources. */
#define LEDC_INT_ALL ((u32)0x0000001F)

/* Bitmask for all externally-enabled LEDC interrupt sources. */
#define LEDC_INT_EXT_EN ((u32)0x0000001D)

/* Checks if the interrupt parameter is within valid range. */
#define IS_LEDC_INTERRUPT ((INT) <= LEDC_INT_ALL)

LEDC LED Number

/* Default number of LEDs connected to LEDC. */
#define LEDC_DEFAULT_LED_NUM (32)

/* Maximum number of LEDs supported by LEDC (1024). */
#define LEDC_MAX_LED_NUM (1024)

/* Checks if the LED number parameter is within valid range. */
#define IS_LEDC_LED_NUM ((NUM > 0) && (NUM <= LEDC_MAX_LED_NUM))

LEDC Output Order

/* Bitmask for the LEDC output byte order field. */
#define LEDC_OUTPUT_ORDER_MASK ((u32)0x0000001C)

/* Sets the LEDC output byte order field value. */
#define LEDC_OUTPUT_ORDER ((u32)((x) & 0x00000007) << 2)

LEDC RGB Mode

/* LEDC RGB output order: GRB. */
#define LEDC_OUTPUT_GRB (0)

/* LEDC RGB output order: GBR. */
#define LEDC_OUTPUT_GBR (1)

/* LEDC RGB output order: RGB. */
#define LEDC_OUTPUT_RGB (2)

/* LEDC RGB output order: BGR. */
#define LEDC_OUTPUT_BGR (3)

/* LEDC RGB output order: RBG. */
#define LEDC_OUTPUT_RBG (4)

/* LEDC RGB output order: BRG. */
#define LEDC_OUTPUT_BRG (5)

/* Checks if the RGB output mode parameter is valid. */
#define IS_LEDC_OUTPUT_MODE ((MODE) == LEDC_OUTPUT_GRB || \
    (MODE) == LEDC_OUTPUT_GBR || \
    (MODE) == LEDC_OUTPUT_RGB || \
    (MODE) == LEDC_OUTPUT_BGR || \
    (MODE) == LEDC_OUTPUT_RBG || \
    (MODE) == LEDC_OUTPUT_BRG)

LEDC Reset Count

/* Minimum LEDC LED reset count value (0). */
#define LEDC_MIN_RESET_CNT ((u32)0)

/* Maximum LEDC LED reset count value (0x3FFF). */
#define LEDC_MAX_RESET_CNT ((u32)0x3FFF)

/* Checks if the reset count value is within valid range. */
#define IS_LEDC_RESET_VAL ((NUM) <= LEDC_MAX_RESET_CNT)

LEDC Transfer Mode

/* LEDC CPU transfer mode. */
#define LEDC_CPU_MODE (0)

/* LEDC DMA transfer mode. */
#define LEDC_DMA_MODE (1)

/* Checks if the transfer mode parameter is valid. */
#define IS_LEDC_TRANS_MODE (((MODE) == LEDC_CPU_MODE ||\
    (MODE) == LEDC_DMA_MODE))

LEDC Wait Data Time Count

/* Minimum LEDC wait-data timeout count value (0). */
#define LEDC_MIN_WAIT_DATA_TIME_CNT ((u32)0)

/* Maximum LEDC wait-data timeout count value (0x7FFF). */
#define LEDC_MAX_WAIT_DATA_TIME_CNT ((u32)0x7FFF)

/* Checks if the wait-data time count is within valid range. */
#define IS_LEDC_WAIT_DATA_TIME_VAL ((NUM) <= LEDC_MAX_WAIT_DATA_TIME_CNT)

LEDC Wait Time0 Count

/* Minimum LEDC wait time0 count value (0). */
#define LEDC_MIN_WAIT_TIME0_CNT ((u32)0)

/* Maximum LEDC wait time0 count value (0x1FF). */
#define LEDC_MAX_WAIT_TIME0_CNT ((u32)0x1FF)

/* Checks if the wait time0 count is within valid range. */
#define IS_LEDC_WAIT_TIME0_VAL ((NUM) <= LEDC_MAX_WAIT_TIME0_CNT)

LEDC Wait Time1 Count

/* Minimum LEDC wait time1 count value (0). */
#define LEDC_MIN_WAIT_TIME1_CNT ((u32)0)

/* Maximum LEDC wait time1 count value (0x7FFFFFFF). */
#define LEDC_MAX_WAIT_TIME1_CNT ((u32)0x7FFFFFFF)

/* Checks if the wait time1 count is within valid range. */
#define IS_LEDC_WAIT_TIME1_VAL ((NUM) <= LEDC_MAX_WAIT_TIME1_CNT)

LEDC Exported Functions

void LEDC_ClearINT(LEDC_TypeDef *LEDCx, u32 LEDC_IT)

Clear the LEDC's interrupt bits.

参数:

LEDCx -- Selected LEDC peripheral.
LEDC_IT --
Specifies the LEDCx interrupt sources to be cleared. This parameter can be one or combinations of the following values:
- BIT_LEDC_FIFO_OVERFLOW_INT_EN: LEDC FIFO Overflow Interrupt
- BIT_LEDC_WAITDATA_TIMEOUT_INT_EN: LEDC Wait Data Timeout Interrupt
- BIT_LEDC_CPUREQ_FIFO_INT_EN: LEDC CPU Request Interrupt
- BIT_LEDC_TRANS_FINISH_INT_EN: LEDC Transfer Finish Interrupt

void LEDC_Cmd(LEDC_TypeDef *LEDCx, u8 NewState)

Enable or disable LEDC peripheral.

参数:

LEDCx -- Selected LEDC peripheral.
NewState -- New state of the operation mode. This parameter can be: ENABLE or DISABLE.

u32 LEDC_GetFIFOLevel(LEDC_TypeDef *LEDCx)

Get LEDC FIFO Level.

参数:

LEDCx -- Selected LEDC peripheral.

返回:

LEDC FIFO level

u32 LEDC_GetINT(LEDC_TypeDef *LEDCx)

Get LEDC interrupt status.

参数:

LEDCx -- Selected LEDC peripheral.

返回:

Current interrupt status, each bit of this value represents one interrupt status:

bit 17 : FIFO_EMPTY FIFO empty status flag.

0 : FIFO is not empty
1 : FIFO is empty

bit 16 : FIFO_FULL FIFO full status flag.

0 : FIFO is not full
1 : FIFO is full

bit 3 : FIFO_OVERFLOW_INT FIFO overflow interrupt.

0 : FIFO does not overflow
1 : FIFO overflows

bit 2 : WAITDATA_TIMEOUT_INT Wait data timeout interrupt.

0 : LEDC is not timeout
1 : LEDC is timeout

bit 1 : FIFO_CPUREQ_INT CPU request interrupt when FIFO space is less than threshold.

0 : FIFO doesn't request CPU for data
1 : FIFO requests CPU to transfer data

bit 0 : LED_TRANS_FINISH_INT Transfer done interrupt.

0 : Data transfer has not completed
1 : Data transfer has completed

u32 LEDC_GetTransferMode(LEDC_TypeDef *LEDCx)

Get LEDC transfer mode.

参数:

LEDCx -- Selected LEDC peripheral.

返回:

LEDC transfer mode:

LEDC_DMA_MODE
LEDC_CPU_MODE

void LEDC_INTConfig(LEDC_TypeDef *LEDCx, u32 LEDC_IT, u32 NewState)

ENABLE/DISABLE LEDC's interrupt bits.

参数:

LEDCx -- Selected LEDC peripheral.
LEDC_IT --
Specifies the LEDCx interrupt sources to be enabled or disabled. This parameter can be one or combinations of the following values:
- BIT_LEDC_FIFO_OVERFLOW_INT_EN: LEDC FIFO Overflow Interrupt
- BIT_LEDC_WAITDATA_TIMEOUT_INT_EN: LEDC Wait Data Timeout Interrupt
- BIT_LEDC_CPUREQ_FIFO_INT_EN: LEDC CPU Request Interrupt
- BIT_LEDC_TRANS_FINISH_INT_EN: LEDC Transfer Finish Interrupt
NewState --
Specifies the state of the interrupt. This parameter can be one of the following values:
- ENABLE
- DISABLE

void LEDC_Init(LEDC_TypeDef *LEDCx, LEDC_InitTypeDef *LEDC_InitStruct)

Initialize the LEDC peripheral according to the specified parameters in the LEDC_InitStruct.

参数:

LEDCx -- Selected LEDC peripheral.
LEDC_InitStruct -- Pointer to a LEDC_InitTypeDef structure that contains the configuration information for the specified LEDC peripheral

void LEDC_LEDReset(LEDC_TypeDef *LEDCx)

Set LEDC Send LED refresh signal.

参数:

LEDCx -- Selected LEDC peripheral.

u32 LEDC_SendData(LEDC_TypeDef *LEDCx, void *data, u32 Len)

Send Specific Data to LEDC FIFO.

参数:

LEDCx -- Selected LEDC peripheral.
data -- LEDCx input source data, only the lower 24bits valid.
Len -- Data length to send.

返回:

Number of data items actually sent to LEDC FIFO.

void LEDC_SetFIFOLevel(LEDC_TypeDef *LEDCx, u8 FifoLevel)

Set LEDC's FIFO Level.

参数:

LEDCx -- Selected LEDC peripheral.
FifoLevel -- LEDCx FIFO level. Value range: 0 to 31. When the number of transmit FIFO entries is greater or equal to this value, DMA request or BIT_LEDC_CPUREQ_FIFO_INT_EN happens. This parameter is recommended to 7 or 15.

void LEDC_SetInputMode(LEDC_TypeDef *LEDCx, u8 order)

Set LEDC Input MSB or LSB order.

参数:

LEDCx -- Selected LEDC peripheral.
order --
This parameter can be one of the following values:
- LEDC_INPUT_LSB: LSB first
- LEDC_INPUT_MSB: MSB first

void LEDC_SetLEDNum(LEDC_TypeDef *LEDCx, u32 Num)

Set LEDC LED Number.

参数:

LEDCx -- Selected LEDC peripheral.
Num -- LEDCx LED number. Value range: 1 to 1024.

void LEDC_SetOutputMode(LEDC_TypeDef *LEDCx, u32 mode)

Set LEDC Output RGB Mode.

参数:

LEDCx -- Selected LEDC peripheral.
mode --
LEDCx Output mode with input GBR mode order. This parameter can be one of the following values:
- LEDC_OUTPUT_GRB: LEDC Output in order of GRB
- LEDC_OUTPUT_GBR: LEDC Output in order of GBR
- LEDC_OUTPUT_RGB: LEDC Output in order of RGB
- LEDC_OUTPUT_BGR: LEDC Output in order of BGR
- LEDC_OUTPUT_RBG: LEDC Output in order of RBG
- LEDC_OUTPUT_BRG: LEDC Output in order of BRG

void LEDC_SetOutputOrder(LEDC_TypeDef *LEDCx, u8 order)

Set LEDC Output data with MSB or LSB order.

参数:

LEDCx -- Selected LEDC peripheral.
order --
Specifies the output order, can be one of the following values:
- LEDC_INPUT_LSB: LEDC input data in order of GRB
- LEDC_INPUT_MSB: LEDC input data in order of GBR

void LEDC_SetPolarity(LEDC_TypeDef *LEDCx, u32 Pol)

Set LEDC Idle Output Level.

参数:

LEDCx -- Selected LEDC peripheral.
Pol --
LEDCx Output level. This parameter can be one of the following values:
- LEDC_IDLE_POLARITY_HIGH: LEDC Idle output High Level
- LEDC_IDLE_POLARITY_LOW: LEDC Idle output Low Level

void LEDC_SetReset_val(LEDC_TypeDef *LEDCx, u32 RstVal)

Set LEDC Reset Time Value.

参数:

LEDCx -- Selected LEDC peripheral.
RstVal -- LEDC reset time Value. Value range is LEDC_MIN_RESET_CNT to LEDC_MAX_RESET_CNT.

void LEDC_SetT0H_val(LEDC_TypeDef *LEDCx, u32 T0hVal)

Set LEDC logic 0 high level time.

参数:

LEDCx -- Selected LEDC peripheral.
T0hVal -- LEDC logic 0 high level time. Value Range is 0 to 0x7F.

void LEDC_SetT0L_val(LEDC_TypeDef *LEDCx, u32 T0lVal)

Set LEDC logic 0 low level time.

参数:

LEDCx -- Selected LEDC peripheral.
T0lVal -- LEDC logic 0 low level time. Value Range is 0 to 0x7F.

void LEDC_SetT1H_val(LEDC_TypeDef *LEDCx, u32 T1hVal)

Set LEDC logic 1 high level time.

参数:

LEDCx -- Selected LEDC peripheral.
T1hVal -- LEDC logic 1 high level time. Value Range is 0 to 0x7F.

void LEDC_SetT1L_val(LEDC_TypeDef *LEDCx, u32 T1lVal)

Set LEDC logic 1 low level time.

参数:

LEDCx -- Selected LEDC peripheral.
T1lVal -- LEDC logic 1 low level time. Value Range is 0 to 0x7F.

void LEDC_SetTotalLength(LEDC_TypeDef *LEDCx, u32 TotalData)

Set LEDC Total Data Length.

参数:

LEDCx -- Selected LEDC peripheral.
TotalData -- LEDCx data length. Value range: 1 to 8192. This specifies total amount of 32-bit data words to transfer.

void LEDC_SetTransferMode(LEDC_TypeDef *LEDCx, u32 mode)

Set LEDC transfer mode.

参数:

LEDCx -- Selected LEDC peripheral.
mode --
This parameter can be one of the following values:
- LEDC_CPU_MODE
- LEDC_DMA_MODE

void LEDC_SetWaitDataTime_val(LEDC_TypeDef *LEDCx, u32 WaitDataVal)

Set LEDC Wait data Time Value.

参数:

LEDCx -- Selected LEDC peripheral.
WaitDataVal -- LEDC wait data. Value range is LEDC_MIN_WAIT_DATA_TIME_CNT to LEDC_MAX_WAIT_DATA_TIME_CNT.

void LEDC_SetWaitTime0_val(LEDC_TypeDef *LEDCx, u32 WaitTime0, u8 NewState)

Set LEDC Wait between Two Packages Time0 Value.

参数:

LEDCx -- Selected LEDC peripheral.
WaitTime0 -- LEDC wait time0. Value range is LEDC_MIN_WAIT_TIME0_CNT to LEDC_MAX_WAIT_TIME0_CNT.
NewState --
Enable or disable wait time between two packages. This parameter can be one of the following values:
- ENABLE
- DISABLE

void LEDC_SetWaitTime1_val(LEDC_TypeDef *LEDCx, u32 WaitTime1, u8 NewState)

Set LEDC Wait between Two Frames Time1 Value.

参数:

LEDCx -- Selected LEDC peripheral.
WaitTime1 -- LEDC wait time1. Value range is LEDC_MIN_WAIT_TIME1_CNT to LEDC_MAX_WAIT_TIME1_CNT.
NewState --
Enable or disable wait time between two frames. This parameter can be one of the following values:
- ENABLE
- DISABLE

void LEDC_SoftReset(LEDC_TypeDef *LEDCx)

Set LEDC soft reset, Force LEDC Enters IDLE State.

参数:

LEDCx -- Selected LEDC peripheral.

备注

LEDC soft reset will clear to 0 after set 1; after LEDC soft reset, LEDC enters idle state, which brings all interrupt status cleared, FIFO read write pointer cleared, finished data count is 0 and LEDC_EN bit is cleared to 0.

void LEDC_StructInit(LEDC_InitTypeDef *LEDC_InitStruct)

Fill each LEDC_InitStruct member with its default value.

参数:

LEDC_InitStruct -- Pointer to an LEDC_InitTypeDef structure which will be initialized.

bool LEDC_TXGDMA_Init(LEDC_TypeDef *LEDCx, PGDMA_InitTypeDef GDMA_InitStruct, void *CallbackData, IRQ_FUN CallbackFunc, u32 *pTxData, u32 Length)

Init and Enable LEDC TX GDMA.

参数:

LEDCx -- Selected LEDC peripheral.
GDMA_InitStruct -- Pointer to a GDMA_InitTypeDef structure that contains the configuration information for the GDMA peripheral.
CallbackData -- GDMA callback data.
CallbackFunc -- GDMA callback function.
pTxData -- Tx Buffer.
Length -- Tx Count.

返回:

Init status:

TRUE: Init success
FALSE: Init fail

void LEDC_WriteData(LEDC_TypeDef *LEDCx, u32 data)

Write Data to LEDC FIFO.

参数:

LEDCx -- Selected LEDC peripheral.
data -- LEDCx input data, only the lower 24bits valid.