功能模块的硬件介绍

I2C（ Inter Integrated Circuit）总线是 PHILIPS 公司开发的一种半双工、双向二线制同步串行总线。I2C 总线传输数据时只需两根信号线，一根是双向数据线 SDA（ serial data），另一根是双向时钟线 SCL（ serial clock）。 SPI 总线有两根线分别用于主从设备之间接收数据和发送数据，而 I2C 总线只使用一根线进行数据收发。

(资料图)

功能模块的使用说明

工程创建

rtthread的numaker-m2354工程模板是下载的其他大佬修改好了的工程，

工程裁剪

使用ENV工具，输入指令menuconfig，弹出如下界面。

选择Hardware Drivers Config

然后选择On-chip peripheral Drivers

选择I2c使能

使能I2C1（我使用的是aht10传感器连接的是SDA和SCL）

使用I2c

官方已经很贴心的实现了I2c的驱动层，drv_I2c.c。

/************************************************************************//*

@copyright (C) 2020 Nuvoton Technology Corp. All rights reserved.

SPDX-License-Identifier: Apache-2.0

Change Logs: Date Author Notes 2020-2-05 HPHuang First version ************************************************************************* * ** / #include #ifdef BSP_USING_I2C #include #include "NuMicro.h" /Private define ---------------------------------------------------------------/ #define LOG_TAG "drv.i2c" #define DBG_ENABLE #define DBG_SECTION_NAME "drv.i2c" #define DBG_LEVEL DBG_ERROR #define DBG_COLOR #include const rt_uint32_t u32I2C_MASTER_STATUS_START = 0x08UL; const rt_uint32_t u32I2C_MASTER_STATUS_REPEAT_START = 0x10UL; const rt_uint32_t u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_ACK = 0x18UL; const rt_uint32_t u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_NACK = 0x20UL; const rt_uint32_t u32I2C_MASTER_STATUS_TRANSMIT_DATA_ACK = 0x28UL; const rt_uint32_t u32I2C_MASTER_STATUS_TRANSMIT_DATA_NACK = 0x30UL; const rt_uint32_t u32I2C_MASTER_STATUS_ARBITRATION_LOST = 0x38UL; const rt_uint32_t u32I2C_MASTER_STATUS_RECEIVE_ADDRESS_ACK = 0x40UL; const rt_uint32_t u32I2C_MASTER_STATUS_RECEIVE_ADDRESS_NACK = 0x48UL; const rt_uint32_t u32I2C_MASTER_STATUS_RECEIVE_DATA_ACK = 0x50UL; const rt_uint32_t u32I2C_MASTER_STATUS_RECEIVE_DATA_NACK = 0x58UL; const rt_uint32_t u32I2C_MASTER_STATUS_BUS_ERROR = 0x00UL; const rt_uint32_t u32I2C_MASTER_STATUS_BUS_RELEASED = 0xF8UL; /* Private typedef --------------------------------------------------------------* / typedef struct _nu_i2c_bus { struct rt_i2c_bus_device parent; I2C_T I2C; struct rt_i2c_msg msg; char device_name; } nu_i2c_bus_t; /Private variables ------------------------------------------------------------/ #ifdef BSP_USING_I2C0 #define I2C0BUS_NAME "i2c0" staticnu_i2c_bus_t nu_i2c0 = { .I2C = I2C0, .device_name = I2C0BUS_NAME, }; #endif /BSP_USING_I2C0 / #ifdef BSP_USING_I2C1 #define I2C1BUS_NAME "i2c1" static nu_i2c_bus_t nu_i2c1 = { .I2C = I2C1, .device_name = I2C1BUS_NAME, }; #endif /BSP_USING_I2C1 / #ifdef BSP_USING_I2C2 #define I2C2BUS_NAME "i2c2" static nu_i2c_bus_t nu_i2c2 = { .I2C = I2C2, .device_name = I2C2BUS_NAME, }; #endif /BSP_USING_I2C2 / /Private functions ------------------------------------------------------------* / #if (defined(BSP_USING_I2C0) || defined(BSP_USING_I2C1) || defined(BSP_USING_I2C2)) static rt_size_t nu_i2c_mst_xfer(struct rt_i2c_bus_device *bus, struct rt_i2c_msg msgs[], rt_uint32_t num); static const struct rt_i2c_bus_device_ops nu_i2c_ops = { .master_xfer = nu_i2c_mst_xfer, .slave_xfer = NULL, .i2c_bus_control = NULL, }; static rt_err_t nu_i2c_configure(nu_i2c_bus_t *bus) { RT_ASSERT(bus != RT_NULL); bus->parent.ops = &nu_i2c_ops; I2C_Open(bus->I2C, 100000); return RT_EOK; } static inline rt_err_t nu_i2c_wait_ready_with_timeout(nu_i2c_bus_t *bus) { rt_tick_t start = rt_tick_get(); while (!(bus->I2C->CTL0 & I2C_CTL0_SI_Msk)) { if ((rt_tick_get() - start) > bus->parent.timeout) { LOG_E("ni2c: timeout!n"); return -RT_ETIMEOUT; } } return RT_EOK; } static inline rt_err_t nu_i2c_send_data(nu_i2c_bus_t *nu_i2c, rt_uint8_t data) { I2C_SET_DATA(nu_i2c->I2C, data); I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_SI); return nu_i2c_wait_ready_with_timeout(nu_i2c); } static rt_err_t nu_i2c_send_address(nu_i2c_bus_t *nu_i2c, struct rt_i2c_msg msg) { rt_uint16_t flags = msg->flags; rt_uint16_t ignore_nack = msg->flags & RT_I2C_IGNORE_NACK; rt_uint8_t addr1, addr2; rt_err_t ret; if (flags & RT_I2C_ADDR_10BIT) { nu_i2c->I2C->CTL1 |= I2C_CTL1_ADDR10EN_Msk; addr1 = 0xf0 | ((msg->addr >> 7) & 0x06); addr2 = msg->addr & 0xff; LOG_D("address1: %d, address2: %dn", addr1, addr2); ret = nu_i2c_send_data(nu_i2c, addr1); if (ret != RT_EOK) /fortimeout condition / return -RT_EIO; if ((I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_ACK) && !ignore_nack) { LOG_E("NACK: sending first address failedn"); return -RT_EIO; } ret = nu_i2c_send_data(nu_i2c, addr2); if (ret != RT_EOK) /for timeout condition / return -RT_EIO; if ((I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_ACK) && !ignore_nack) { LOG_E("NACK: sending second address failedn"); return -RT_EIO; } if (flags & RT_I2C_RD) { LOG_D("send repeated START signaln"); I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_STA_SI); ret = nu_i2c_wait_ready_with_timeout(nu_i2c); if (ret != RT_EOK) /for timeout condition / return -RT_EIO; if ((I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_REPEAT_START) && !ignore_nack) { LOG_E("sending repeated START failedn"); return -RT_EIO; } addr1 |= 0x01; ret = nu_i2c_send_data(nu_i2c, addr1); if (ret != RT_EOK) /for timeout condition / return -RT_EIO; if ((I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_RECEIVE_ADDRESS_ACK) && !ignore_nack) { LOG_E("NACK: sending read address failedn"); return -RT_EIO; } } } else { /7-bit addr / addr1 = msg->addr << 1; if (flags & RT_I2C_RD) addr1 |= 1; /Send device address / ret = nu_i2c_send_data(nu_i2c, addr1); /Send Address / if (ret != RT_EOK) /for timeout condition */ return -RT_EIO; if ((I2C_GET_STATUS(nu_i2c->I2C) != ((flags & RT_I2C_RD) ? u32I2C_MASTER_STATUS_RECEIVE_ADDRESS_ACK : u32I2C_MASTER_STATUS_TRANSMIT_ADDRESS_ACK)) && !ignore_nack) { LOG_E("sending address failedn"); return -RT_EIO; } } return RT_EOK; } static rt_size_t nu_i2c_mst_xfer(struct rt_i2c_bus_device *bus, struct rt_i2c_msg msgs[], rt_uint32_t num) { struct rt_i2c_msg msg; nu_i2c_bus_t nu_i2c; rt_size_t i; rt_uint32_t cnt_data; rt_uint16_t ignore_nack; rt_err_t ret; RT_ASSERT(bus != RT_NULL); nu_i2c = (nu_i2c_bus_t ) bus; nu_i2c->msg = msgs; nu_i2c->I2C->CTL0 |= I2C_CTL0_STA_Msk | I2C_CTL0_SI_Msk; ret = nu_i2c_wait_ready_with_timeout(nu_i2c); if (ret != RT_EOK) /for timeout condition / { rt_set_errno(-RT_ETIMEOUT); return 0; } if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_START) { i = 0; LOG_E("Send START Failed"); return i; } for (i = 0; i < num; i++) { msg = &msgs[i]; ignore_nack = msg->flags & RT_I2C_IGNORE_NACK; if (!(msg->flags & RT_I2C_NO_START)) { if (i) { I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_STA_SI); ret = nu_i2c_wait_ready_with_timeout(nu_i2c); if (ret != RT_EOK) /for timeout condition / break; if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_REPEAT_START) { i = 0; LOG_E("Send repeat START Fail"); break; } } if ((RT_EOK != nu_i2c_send_address(nu_i2c, msg)) && !ignore_nack) { i = 0; LOG_E("Send Address Fail"); break; } } if (nu_i2c->msg[i].flags & RT_I2C_RD) /Receive Bytes / { rt_uint32_t do_rd_nack = (i == (num - 1)); for (cnt_data = 0 ; cnt_data < (nu_i2c->msg[i].len) ; cnt_data++) { do_rd_nack += (cnt_data == (nu_i2c->msg[i].len - 1)); /NACK after last byte for hardware setting / if (do_rd_nack == 2) { I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_SI); } else { I2C_SET_CONTROL_REG(nu_i2c->I2C, I2C_CTL_SI_AA); } ret = nu_i2c_wait_ready_with_timeout(nu_i2c); if (ret != RT_EOK) /for timeout condition / break; if (nu_i2c->I2C->CTL0 & I2C_CTL_AA) { if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_RECEIVE_DATA_ACK) { i = 0; break; } } else { if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_RECEIVE_DATA_NACK) { i = 0; break; } } nu_i2c->msg[i].buf[cnt_data] = nu_i2c->I2C->DAT; } } else /Send Bytes / { for (cnt_data = 0 ; cnt_data < (nu_i2c->msg[i].len) ; cnt_data++) { /Send register number and MSB of data / ret = nu_i2c_send_data(nu_i2c, (uint8_t)(nu_i2c->msg[i].buf[cnt_data])); if (ret != RT_EOK) /for timeout condition / break; if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_TRANSMIT_DATA_ACK && !ignore_nack ) /Send aata and get Ack / { i = 0; break; } } } } I2C_STOP(nu_i2c->I2C); RT_ASSERT(I2C_GET_STATUS(nu_i2c->I2C) == u32I2C_MASTER_STATUS_BUS_RELEASED); if (I2C_GET_STATUS(nu_i2c->I2C) != u32I2C_MASTER_STATUS_BUS_RELEASED) { i = 0; } nu_i2c->msg = RT_NULL; nu_i2c->I2C->CTL1 = 0; / clear all submodes like 10 bit mode/ return i; } #endif /Public functions -------------------------------------------------------------/ int rt_hw_i2c_init(void) { rt_err_t ret = RT_ERROR; #if defined(BSP_USING_I2C0) SYS_UnlockReg(); SYS_ResetModule(I2C0_RST); SYS_LockReg(); nu_i2c_configure(&nu_i2c0); ret = rt_i2c_bus_device_register(&nu_i2c0.parent, nu_i2c0.device_name); RT_ASSERT(RT_EOK == ret); #endif /BSP_USING_I2C0 / #if defined(BSP_USING_I2C1) SYS_UnlockReg(); SYS_ResetModule(I2C1_RST); SYS_LockReg(); nu_i2c_configure(&nu_i2c1); ret = rt_i2c_bus_device_register(&nu_i2c1.parent, nu_i2c1.device_name); RT_ASSERT(RT_EOK == ret); #endif /BSP_USING_I2C1 / #if defined(BSP_USING_I2C2) SYS_UnlockReg(); SYS_ResetModule(I2C2_RST); SYS_LockReg(); nu_i2c_configure(&nu_i2c2); ret = rt_i2c_bus_device_register(&nu_i2c2.parent, nu_i2c2.device_name); RT_ASSERT(RT_EOK == ret); #endif /BSP_USING_I2C2 / return ret; } INIT_DEVICE_EXPORT(rt_hw_i2c_init); #endif /BSP_USING_I2C */ 使用官网提供的I2c测试代码，设备名称为i2c1

/*

Copyright (c) 2006-2018, RT-ThreadDevelopment Team

SPDX-License-Identifier: Apache-2.0

Change Logs: Date Author Notes 2018-08-15 misonyo first implementation./ /程序清单：这是一个 I2C 设备使用例程 例程导出了 i2c_aht10_sample 命令到控制终端 命令调用格式：i2c_aht10_sample i2c1 命令解释：命令第二个参数是要使用的I2C总线设备名称，为空则使用默认的I2C总线设备 程序功能：通过 I2C 设备读取温湿度传感器aht10 的温湿度数据并打印/ #include #include #define AHT10_I2C_BUS_NAME "i2c1" /传感器连接的I2C总线设备名称 / #define AHT10_ADDR 0x38 /从机地址 / #define AHT10_CALIBRATION_CMD 0xE1 /校准命令 / #define AHT10_NORMAL_CMD 0xA8 /一般命令 / #define AHT10_GET_DATA 0xAC /获取数据命令 */ static struct rt_i2c_bus_device i2c_bus = RT_NULL; /I2C总线设备句柄 / static rt_bool_t initialized = RT_FALSE; /传感器初始化状态 / /写传感器寄存器 */ static rt_err_t write_reg(struct rt_i2c_bus_device *bus, rt_uint8_t reg, rt_uint8_t data) { rt_uint8_t buf[3]; struct rt_i2c_msg msgs; buf[0] = reg; //cmd buf[1] = data[0]; buf[2] = data[1]; msgs.addr = AHT10_ADDR; msgs.flags = RT_I2C_WR; msgs.buf = buf; msgs.len = 3; /调用I2C设备接口传输数据 / if (rt_i2c_transfer(bus, &msgs, 1) == 1) { return RT_EOK; } else { return -RT_ERROR; } } /读传感器寄存器数据 */ static rt_err_t read_regs(struct rt_i2c_bus_device *bus, rt_uint8_t len, rt_uint8_t buf) { struct rt_i2c_msg msgs; msgs.addr = AHT10_ADDR; msgs.flags = RT_I2C_RD; msgs.buf = buf; msgs.len = len; /调用I2C设备接口传输数据 */ if (rt_i2c_transfer(bus, &msgs, 1) == 1) { return RT_EOK; } else { return -RT_ERROR; } } static void read_temp_humi(float *cur_temp, float cur_humi) { rt_uint8_t temp[6]; write_reg(i2c_bus, AHT10_GET_DATA, 0); /发送命令 / read_regs(i2c_bus, 6, temp); /获取传感器数据 / /湿度数据转换 */cur_humi = (temp[1] << 12 | temp[2] << 4 | (temp[3] & 0xf0) >> 4) * 100.0 / (1 << 20); /温度数据转换 */ *cur_temp = ((temp[3] & 0xf) << 16 | temp[4] << 8 | temp[5]) * 200.0 / (1 << 20) - 50; } static void aht10_init(const char name) { rt_uint8_t temp[2] = {0, 0}; /查找I2C总线设备，获取I2C总线设备句柄 */ i2c_bus = (struct rt_i2c_bus_device *)rt_device_find(name); if (i2c_bus == RT_NULL) { rt_kprintf("can"t find %s device!n", name); } else { write_reg(i2c_bus, AHT10_NORMAL_CMD, temp); rt_thread_mdelay(400); temp[0] = 0x08; temp[1] = 0x00; write_reg(i2c_bus, AHT10_CALIBRATION_CMD, temp); rt_thread_mdelay(400); initialized = RT_TRUE; } } static void i2c_aht10_sample(int argc, char argv[]) { float humidity, temperature; char name[RT_NAME_MAX]; humidity = 0.0; temperature = 0.0; if (argc == 2) { rt_strncpy(name, argv[1], RT_NAME_MAX); } else { rt_strncpy(name, AHT10_I2C_BUS_NAME, RT_NAME_MAX); } if (!initialized) { /传感器初始化 / aht10_init(name); } if (initialized) { /读取温湿度数据 / read_temp_humi(&temperature, &humidity); rt_kprintf("read aht10 sensor humidity : %d.%d %%n", (int)humidity, (int)(humidity * 10) % 10); rt_kprintf("read aht10 sensor temperature: %d.%d n", (int)temperature, (int)(temperature * 10) % 10); } else { rt_kprintf("initialize sensor failed!n"); } } /导出到 msh 命令列表中 */ MSH_CMD_EXPORT(i2c_aht10_sample, i2c aht10 sample);

编译下载

在FINSH控制台下输入i2c_aht10_sample获取温度湿度

完成模块功能的演示

观察温湿度变化，I2c测试成功