普冉PY32系列(八) GPIO模拟和硬件SPI方式驱动无线收发芯片XN297LBW

技术分享 2年前 (2023-10-16) 0 999+

XN297LBW

XN297LBW 是一个SOP8封装的2.4GHz频段无线收发芯片, 价格在1元左右, 适用于低成本应用. 虽然磐启已经发布了 XN297L 的下一代产品 PAN1026, 但是市面上基本上见不到后者的身影, 零售能买到的还是 XN297L.

生产商是上海磐启, 产品页地址: https://wiki.panchip.com/ble-lite/2-4g-t-rx/xn297l_series/

磐启对 XN297L 的产品介绍: "工作在 2.400~2.483GHz 世界通用 ISM 频段的单片无线收发芯片, XN297L采用嵌入式基带协议引擎, 适用于超低功耗无线应用. 采用 GFSK 调制, 可配置频率信道, 输出功率和接口数据速率等射频参数. XN297L 支持 2Mbps, 1Mbps 和 250Kbps 的数据速率. 对于长距离应用, 输出功率可以调节高达 11dBm, 对于短距离和超低功率应用, 输出功率可以低至-23dBm."

XN297LBW 主要特性

无线
- 通信频段：2.400GHz~2.483GHz
- 数据速率：2Mbps,1Mbps,250Kbps
- 调制方式：GFSK
发射器
- 输出功率：11, 9, 5, -1, -10 or -23dBm
- 18mA@2dBm
- 30mA@9dBm
接收器
- -83dBm@2Mbps
- -87dBm@1Mbps
- -91dBm@250Kbps
协议引擎
- 支持1到32字节或64字节数据长度
- 支持自动应答及自动重传
- 6个接收数据通道构成1:6的星状网络
电源管理
- 工作电压：2.3~3.3V
- 2uA断电模式
- 30uA待机-Ⅰ模式
主机接口
- 支持3引脚SPI, 4Mbps SPI接口速率
- 支持两个独立的32字节TX和RX FIFOs
- 支持一个64字节的TX和RX FIFOs
封装
- SOP8

这里要注意的几点:

工作电压是3.3V, 不要错接5V.
SPI速率为4MHz, 实测上限不会比4MHz高多少, 在6MHz频率时大概率SPI通信错误导致不能工作.
TX FIFO 与NRF24L01相比只有两个32字节, 而NRF24L01是3个32字节. 性能相对缩水.

PIN脚定义和应用电路

PIN脚定义

VDD 和 VSS 分别接 VCC 和 GND
XC1 和 XC2 接晶振
ANT 接天线
用于MCU接口通信的只有 CSN, SCK 和 DATA 这三个PIN

应用电路

模块实物

嘉立创打样的测试模块 (项目地址 https://oshwhub.com/iosetting/xn297lbw-xl2400-evb)

使用PY32F0驱动XN297LBW

XN297L最新的SDK可以从磐启的论坛下载论坛›BLE-Lite系列2.4GHz TRX›XN297L›XN297L_SDK. 因为面向的主要是低成本应用, 大多数搭配的MCU为廉价的8位8051, 不一定有硬件SPI, 为了保证兼容在SDK中使用的都是GPIO模拟SPI方式进行驱动. 但是实际上是可以通过硬件SPI方式进行驱动的.

以下分别对GPIO模拟和硬件SPI方式的驱动进行介绍.

硬件准备

XN297LBW模块
PY32F002A/PY32F003/PY32F030 系列MCU的开发板, 建议在验证阶段使用 20PIN 及以上封装的型号, 避免PIN脚复用引起的干扰. 跑通后再迁移到低PIN型号
USB2TTL模块, 用于观察输出
以上硬件需要两套, 测试中分别用于接收和发送

下面以PY32F002A为例. 代码不需调整可以直接运行于 PY32F003x 和 PY32F030x 系列的其它型号.

GPIO模拟方式

接线

注意电源使用3.3V

PY32          XN297LBW SOP8 PA1   ------> CLK/SCK PA6   ------> CSN/NSS PA7   ------> DATA/MOSI                USB2TTL PA2(TX) ----> RX PA3(RX) ----> TX

代码说明

SDK代码中使用的MCU是STM8L, 需要迁移到 PY32F002A.

将 xn297l.h 中的 GPIO 设置换为PY32F002A的PIN脚

#define XN297L_DATA_OUT()        LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_7, LL_GPIO_MODE_OUTPUT) #define XN297L_DATA_IN()         LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_7, LL_GPIO_MODE_INPUT) #define XN297L_DATA_LOW()        LL_GPIO_ResetOutputPin(GPIOA, LL_GPIO_PIN_7) #define XN297L_DATA_HIGH()       LL_GPIO_SetOutputPin(GPIOA, LL_GPIO_PIN_7) #define XN297L_DATA_READ()       LL_GPIO_IsInputPinSet(GPIOA, LL_GPIO_PIN_7)  #define XN297L_SCK_LOW()         LL_GPIO_ResetOutputPin(GPIOA, LL_GPIO_PIN_1) #define XN297L_SCK_HIGH()        LL_GPIO_SetOutputPin(GPIOA, LL_GPIO_PIN_1)  #define XN297L_CSN_LOW()         LL_GPIO_ResetOutputPin(GPIOA, LL_GPIO_PIN_6) #define XN297L_CSN_HIGH()        LL_GPIO_SetOutputPin(GPIOA, LL_GPIO_PIN_6)  #define XN297L_CE_LOW()          XN297L_WriteReg(XN297L_CMD_CE_FSPI_OFF, 0) #define XN297L_CE_HIGH()         XN297L_WriteReg(XN297L_CMD_CE_FSPI_ON, 0)

在 main.c 中增加GPIO初始化

static void APP_GPIOConfig(void) {   LL_GPIO_InitTypeDef GPIO_InitStruct;    /* PA1 CLK */   GPIO_InitStruct.Pin = LL_GPIO_PIN_1;   GPIO_InitStruct.Mode = LL_GPIO_MODE_OUTPUT;   GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;   GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;   LL_GPIO_Init(GPIOA, &GPIO_InitStruct);   /* PA6 CSN */   GPIO_InitStruct.Pin = LL_GPIO_PIN_6;   LL_GPIO_Init(GPIOA, &GPIO_InitStruct);   /* PA7 DATA */   GPIO_InitStruct.Pin = LL_GPIO_PIN_7;   GPIO_InitStruct.Mode = LL_GPIO_MODE_INPUT;   LL_GPIO_Init(GPIOA, &GPIO_InitStruct); }

使用GPIO模拟SPI的字节写

/**  * Emulate SPI Write on GPIO pins  */ void XN297L_WriteByte(uint8_t value) {     uint8_t i = 0;     XN297L_SCK_LOW();     XN297L_DATA_OUT();     for (i = 0; i < 8; i++)     {         XN297L_SCK_LOW();         if (value & 0x80)         {             XN297L_DATA_HIGH();         }         else         {             XN297L_DATA_LOW();         }         XN297L_SCK_HIGH();         value = value << 1;     }     XN297L_SCK_LOW(); }

模拟字节读. 这里有个细节, 在XN297L_SCK_HIGH();之后加一个__NOP();, 如果没有这个NOP(), PY32F0在低频率(8MHz和24MHz)的时候容易产生读取错误.

/**  * Emulate SPI Read on GPIO pins  */ uint8_t XN297L_ReadByte(void) {     uint8_t i = 0, RxData = 0;      XN297L_DATA_IN();     for (i = 0; i < 8; i++)     {         RxData = RxData << 1;         XN297L_SCK_HIGH();         __NOP();         if (XN297L_DATA_READ())         {             RxData |= 0x01;         }         else         {             RxData &= 0xfe;         }         XN297L_SCK_LOW();     }     return RxData; }

XN297L 的初始化. 这部分是相对固定的流程, 可以根据自己的需要进行调整, 但是在测试阶段务必保持接收端和发送端的配置一致. 这里在SDK的代码上做了一些修改, 开启了发送的重试和ACK.

// 这部分来自于手册 "XN297L 软件设计和调试参考" const uint8_t      BB_cal_data[]    = {0x12,0xED,0x67,0x9C,0x46},     RF_cal_data[]    = {0xF6,0x3F,0x5D},     RF_cal2_data[]   = {0x45,0x21,0xEF,0x2C,0x5A,0x42},     Dem_cal_data[]   = {0x01},     Dem_cal2_data[]  = {0x0B,0xDF,0x02};  void XN297L_Init(void) {     XN297L_WriteReg(XN297L_CMD_RST_FSPI, 0x5A); // Soft reset     XN297L_WriteReg(XN297L_CMD_RST_FSPI, 0XA5);      XN297L_WriteReg(XN297L_CMD_FLUSH_TX, 0);     XN297L_WriteReg(XN297L_CMD_FLUSH_RX, 0);     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_STATUS, 0x70);       // Clear status flags     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_EN_AA, 0x3F);        // AutoAck on all pipes     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_EN_RXADDR, 0x3F);    // Enable all pipes (P0 ~ P5, bit0 ~ bit5)     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_SETUP_AW, XN297L_SETUP_AW_5BYTE); // Address width     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_RF_CH, 78);          // Channel 78, 2478M HZ     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_RX_PW_P0, XN297L_PLOAD_WIDTH ); // Payload width of P0     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_RX_PW_P1, XN297L_PLOAD_WIDTH ); // Payload width of P1     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_RX_PW_P2, XN297L_PLOAD_WIDTH ); // Payload width of P2     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_RX_PW_P3, XN297L_PLOAD_WIDTH ); // Payload width of P3     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_RX_PW_P4, XN297L_PLOAD_WIDTH ); // Payload width of P4     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_RX_PW_P5, XN297L_PLOAD_WIDTH ); // Payload width of P5      XN297L_WriteFromBuf(XN297L_CMD_W_REGISTER | XN297L_REG_BB_CAL,    BB_cal_data,  sizeof(BB_cal_data));     XN297L_WriteFromBuf(XN297L_CMD_W_REGISTER | XN297L_REG_RF_CAL2,   RF_cal2_data, sizeof(RF_cal2_data));     XN297L_WriteFromBuf(XN297L_CMD_W_REGISTER | XN297L_REG_DEM_CAL,   Dem_cal_data, sizeof(Dem_cal_data));     XN297L_WriteFromBuf(XN297L_CMD_W_REGISTER | XN297L_REG_RF_CAL,    RF_cal_data,  sizeof(RF_cal_data));     XN297L_WriteFromBuf(XN297L_CMD_W_REGISTER | XN297L_REG_DEM_CAL2,  Dem_cal2_data,sizeof(Dem_cal2_data));     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_DYNPD, 0x00); // Dynamic payload width: off     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_RF_SETUP,  XN297L_RF_POWER_P_9|XN297L_RF_DR_1M); // 9dbm 1Mbps     XN297L_WriteReg(XN297L_CMD_ACTIVATE, 0x73);      XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_SETUP_RETR, 0x10|0x05); // Retry interval 500µs, 5 times      if(XN297L_PLOAD_WIDTH >32)     {         XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_FEATURE, XN297L_FEATURE_BIT5_CE_SOFT|XN297L_FEATURE_BIT43_DATA_64BYTE);     }     else     {         XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_FEATURE, XN297L_FEATURE_BIT5_CE_SOFT);     } }

数据发送函数. 因为前面开启了重试和ACK, 这里做了一个等待发送结果的轮询和超时判断

uint8_t XN297L_TxData(uint8_t *ucPayload, uint8_t length) {     uint8_t y = 100, status = 0;     XN297L_CE_HIGH();     __NOP();     XN297L_WriteFromBuf(XN297L_CMD_W_TX_PAYLOAD, ucPayload, length);     // Retry until timeout     while (y--)     {         LL_mDelay(1);         status = XN297L_ReadStatus();         // If TX successful or retry timeout, exit         if ((status & (XN297L_FLAG_MAX_RT | XN297L_FLAG_TX_DS)) != 0)         {             //printf(" %d %02xrn", y, status);             break;         }     }     XN297L_WriteReg(XN297L_CMD_FLUSH_TX, 0);     XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_STATUS, 0x70);     XN297L_CE_LOW();     return status; }

数据接收. 因为接收使用的是轮询, 所以这里只是简单地判断了接收状态, 在收到数据时读取数据.

uint8_t XN297L_DumpRxData(void) {     uint8_t status, rxplWidth;     status = XN297L_ReadStatus();     if (status & XN297L_FLAG_RX_DR)     {         XN297L_WriteReg(XN297L_CMD_W_REGISTER | XN297L_REG_STATUS, status);         rxplWidth = XN297L_ReadReg(XN297L_CMD_R_RX_PL_WID);         XN297L_ReadToBuf(XN297L_CMD_R_RX_PAYLOAD, xbuf, rxplWidth);     }     return status; }

完整代码

XN297L 示例代码的 GitHub 仓库地址: https://github.com/IOsetting/py32f0-template/tree/main/Examples/PY32F0xx/LL/GPIO/XN297LBW_Wireless

运行测试

修改 main.c 中的模式设置, 0为接收, 1为发送, 分别写入至两个PY32F002A开发板, 观察UART的输出.

// 0:RX, 1:TX #define XN297L_MODE 0

接收端在每次接收到数据时, 输出第1,2,31个字节的值; 发送端每发送255组数据(每组32字节)后, 会显示发送成功的个数(十六进制), 这个输出可以用于计算发送成功率, 以及发送速度.

硬件SPI方式

接线

接线方式使用4线制全双工, PY32的MOSI和MISO都接到XN297LBW的DATA, 但是在MOSI(PA7)上串一个1K的电阻. 对于使用SPI协议的三线连接, 如果半双工SPI有问题, 都可以用这种接线试试全双工方式通信. 从实际测试看, XN297LBW 支持这种接线方式.

PY32                XN297LBW SOP8 PA0   ------------> DATA/MOSI PA7   ---> 1KR ---> DATA/MOSI PA1   ------------> CLK/SCK PA6   ------------> CSN/NSS                      USB2TTL PA2(TX) ----------> RX PA3(RX) ----------> TX

代码说明

SPI接口的初始化. 注意SPI的时钟频率不要超过4MHz

/**  * SPI1 Alternative Function Pins  * SPI1_SCK:  PA1_AF0, PA2_AF10, PA5_AF0, PA9_AF10, PB3_AF0  * SPI1_MISO: PA0_AF10, PA6_AF0, PA7_AF10, PA11_AF0, PA13_AF10, PB4_AF0  * SPI1_MOSI: PA1_AF10, PA2_AF0, PA3_AF10, PA7_AF0, PA8_AF10, PA12_AF0, PB5_AF0  * SPI1_NSS:  PA4_AF0, PA10_AF10, PA15_AF0, PB0_AF0, PF1_AF10, PF3_AF10 */ static void APP_SPI_Config(void) {   LL_SPI_InitTypeDef SPI_InitStruct = {0};   LL_GPIO_InitTypeDef GPIO_InitStruct = {0};    LL_APB1_GRP2_EnableClock(LL_APB1_GRP2_PERIPH_SPI1);    // PA1 SCK   GPIO_InitStruct.Pin = LL_GPIO_PIN_1;   GPIO_InitStruct.Mode = LL_GPIO_MODE_ALTERNATE;   GPIO_InitStruct.Speed = LL_GPIO_SPEED_FREQ_HIGH;   GPIO_InitStruct.OutputType = LL_GPIO_OUTPUT_PUSHPULL;   GPIO_InitStruct.Pull = LL_GPIO_PULL_UP;   GPIO_InitStruct.Alternate = LL_GPIO_AF_0;   LL_GPIO_Init(GPIOA, &GPIO_InitStruct);   // PA0 MISO   GPIO_InitStruct.Pin = LL_GPIO_PIN_0;   GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;   GPIO_InitStruct.Alternate = LL_GPIO_AF_10;   LL_GPIO_Init(GPIOA, &GPIO_InitStruct);   // PA7 MOSI   GPIO_InitStruct.Pin = LL_GPIO_PIN_7;   GPIO_InitStruct.Pull = LL_GPIO_PULL_NO;   GPIO_InitStruct.Alternate = LL_GPIO_AF_0;   LL_GPIO_Init(GPIOA, &GPIO_InitStruct);   /*    * Full duplex mode, MOSI and MISO both connect to DATA,    * Add one 1KR between MOSI and DATA   */   SPI_InitStruct.TransferDirection = LL_SPI_FULL_DUPLEX;   SPI_InitStruct.Mode = LL_SPI_MODE_MASTER;   SPI_InitStruct.DataWidth = LL_SPI_DATAWIDTH_8BIT;   SPI_InitStruct.ClockPolarity = LL_SPI_POLARITY_LOW;   SPI_InitStruct.ClockPhase = LL_SPI_PHASE_1EDGE;   SPI_InitStruct.NSS = LL_SPI_NSS_SOFT;   // SPI的时钟频率不要超过4MHz   SPI_InitStruct.BaudRate = LL_SPI_BAUDRATEPRESCALER_DIV16;   SPI_InitStruct.BitOrder = LL_SPI_MSB_FIRST;   LL_SPI_Init(SPI1, &SPI_InitStruct);   LL_SPI_Enable(SPI1); }

硬件SPI方式的字节读写

uint8_t SPI_TxRxByte(uint8_t data) {   uint8_t SPITimeout = 0xFF;   /* Check the status of Transmit buffer Empty flag */   while (READ_BIT(SPI1->SR, SPI_SR_TXE) == RESET)   {     if (SPITimeout-- == 0)       return 0;   }   LL_SPI_TransmitData8(SPI1, data);   SPITimeout = 0xFF;   while (READ_BIT(SPI1->SR, SPI_SR_RXNE) == RESET)   {     if (SPITimeout-- == 0)       return 0;   }   // Read from RX buffer   return LL_SPI_ReceiveData8(SPI1); }

对应XN297L的命令读写改造为调用硬件SPI读写函数

uint8_t XN297L_WriteReg(uint8_t reg, uint8_t value) {     uint8_t reg_val;     XN297L_CSN_LOW();     SPI_TxRxByte(reg);     reg_val = SPI_TxRxByte(value);     XN297L_CSN_HIGH();     return reg_val; }  uint8_t XN297L_ReadReg(uint8_t reg) {     uint8_t reg_val;     XN297L_CSN_LOW();     SPI_TxRxByte(reg);     reg_val = SPI_TxRxByte(XN297L_CMD_NOP);     XN297L_CSN_HIGH();     return reg_val; }