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IIC也是非常常用的一个外设，虽然速度不快，但胜在只需要两个管脚就搞定，还有应答机制。 细想想IIC像极了女票，你回到家，女友给你声问候（起始信号），提到你的名字（addr地址）等你回应，然后和你倒一段苦水，再等你回应，再接着倒，再等你回应，如果她说完之前不理她了，一会她就不高兴了（应答错误）然后和你说了声不理你了（停止位）然后就dy外放去了，有时候交流不畅，女友生气了哄起来也头痛（总线死锁）。所以还是纸片人好。
后面需要用到矩阵按键，又不想mcu太累，还是招个专门的ic来负责吧！tb市场转了一圈，最后谈妥了沁恒的CH450，兼容I2C，最高2M，这价格还要啥自行车了。还有个国产的xxx来着uart接口，运费10元，果断推掉。
下面来看下具体代码USER下新建drv_i2c.c和drv_i2c.h
/* Includes ------------------------------------------------------------------*/
#include "at32f4xx.h"
#include "drv_i2c.h"
#include "at32_board.h"
#include <rthw.h>
#include <rtthread.h>
/**
* [url=home.php?mod=space&uid=159083]@brief[/url] I2C Timeout definition
*/
#define I2C_TIMEOUT_FLAG ((uint32_t)35) /* Timeout 35 ms */
#define I2C_TIMEOUT_ADDR_SLAVE ((uint32_t)10000) /* Timeout 10 s */
#define I2C_TIMEOUT_BUSY_FLAG ((uint32_t)10000) /* Timeout 10 s */
/**
* @brief I2C Event check flag definition
*/
#define I2C_EVT_CHECK_NONE ((uint32_t)0x00000000)
#define I2C_EVT_CHECK_ACKFAIL ((uint32_t)0x00000001)
#define I2C_EVT_CHECK_STOP ((uint32_t)0x00000002)
/**
* @brief us delay used by the I2C.
* @param us: delay x us.
* @retval None
*/
void I2C_Delay(uint32_t us)
{
us *= 300;
while(us!=0){
us--;
}
}
/** @brief Clears the I2C ADDR pending flag.
* @param I2Cx: where x can be 1, 2 or 3 to select the I2C peripheral.
* @retval None
*/
void I2C_ClearADDRFlag(I2C_Type* I2Cx)
{
__IO uint32_t tmpreg;
tmpreg = I2Cx->STS1;
tmpreg = I2Cx->STS2;
}
/** @brief Clears the I2C STOPF pending flag.
* @param I2Cx: where x can be 1, 2 or 3 to select the I2C peripheral.
* @retval None
*/
void I2C_ClearSTOPFlag(I2C_Type* I2Cx)
{
__IO uint32_t tmpreg;
tmpreg = I2Cx->STS1;
tmpreg = I2Cx->CTRL1 |= I2C_CTRL1_PEN;
}
/**
* @brief This function handles I2C Communication Timeout.
* @param I2Cx: where x can be 1, 2 or 3 to select the I2C peripheral.
* @param Flag: specifies the I2C flag to check.
* @param Status: The new Flag status (SET or RESET).
* @param Timeout Timeout duration.
* @retval I2C status.
*/
static I2C_StatusType I2C_WaitOnFlagUntilTimeout(I2C_Type* I2Cx, uint32_t Flag, FlagStatus Status, uint32_t EventCheck, uint32_t Timeout)
{
/* delay 10 us = ms * 100 */
Timeout *= 100;
while(I2C_GetFlagStatus(I2Cx, Flag) == Status)
{
/* Check ACKFAIL Flag */
if(EventCheck & I2C_EVT_CHECK_ACKFAIL)
{
if(I2C_GetFlagStatus(I2Cx, I2C_FLAG_ACKFAIL) == SET)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
/* Clear AF Flag */
I2C_ClearFlag(I2Cx, I2C_FLAG_ACKFAIL);
return I2C_ERROR;
}
}
/* Check STOP Flag */
if(EventCheck & I2C_EVT_CHECK_STOP)
{
if(I2C_GetFlagStatus(I2Cx, I2C_FLAG_STOPF) == SET)
{
/* Clear STOP Flag */
I2C_ClearSTOPFlag(I2Cx);
return I2C_ERROR;
}
}
/* 10 us delay */
I2C_Delay(10);
/* Check for the Timeout */
if((Timeout--) == 0)
{
return I2C_TIMEOUT;
}
}
return I2C_OK;
}
/**
* @brief I2C初始化
* @param None
* @retval None
*/
void I2Cx_Init(void)
{
GPIO_InitType GPIO_InitStructure;
I2C_InitType I2C_InitStructure;
/* I2C_SCL_GPIO_CLK and I2C_SDA_GPIO_CLK Periph clock enable */
RCC_AHBPeriphClockCmd(I2C_GPIO_CLK , ENABLE);
/* 启用I2C时钟 */
RCC_APB1PeriphClockCmd(I2C_CLK, ENABLE);
/* GPIO configuration */
GPIO_InitStructure.GPIO_MaxSpeed = GPIO_MaxSpeed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OutType = GPIO_OutType_OD;
GPIO_InitStructure.GPIO_Pull = GPIO_Pull_NOPULL;
/* Configure I2C pins: SCL */
GPIO_InitStructure.GPIO_Pins = I2C_SCL_PIN;
GPIO_Init(I2C_SCL_GPIO_PORT, &GPIO_InitStructure);
/* Configure I2C pins: SDA */
GPIO_InitStructure.GPIO_Pins = I2C_SDA_PIN;
GPIO_Init(I2C_SDA_GPIO_PORT, &GPIO_InitStructure);
/*引脚复用到IIC*/
GPIO_PinAFConfig(I2C_SCL_GPIO_PORT, I2C_SCL_GPIO_PinsSource, I2C_SCL_GPIO_GPIO_AF);
GPIO_PinAFConfig(I2C_SDA_GPIO_PORT, I2C_SDA_GPIO_PinsSource, I2C_SDA_GPIO_GPIO_AF);
/* I2C configuration */
I2C_InitStructure.I2C_Mode = I2C_Mode_I2CDevice;
I2C_InitStructure.I2C_FmDutyCycle = I2C_FmDutyCycle_2_1;
I2C_InitStructure.I2C_OwnAddr1 = I2C_SLAVE_ADDRESS7;
I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
I2C_InitStructure.I2C_AddrMode = I2C_AddrMode_7bit;
I2C_InitStructure.I2C_BitRate = I2C_SPEED;
/* IIC初始化 */
I2C_Init(I2C_PORT, &I2C_InitStructure);
/* 启用I2C */
I2C_Cmd(I2C_PORT, ENABLE);
}
/**
* @brief Receives in master mode an amount of data in blocking mode.
* @param I2Cx: where x can be 1, 2 or 3 to select the I2C peripheral.
* @param DevAddress Target device address.
* @param pData Pointer to data buffer.
* @param Size Amount of data to be sent.
* @param Timeout Timeout duration.
* @retval I2C status.
*/
I2C_StatusType I2C_Receive(I2C_Type* I2Cx, uint16_t DevAddress, uint8_t *pData, uint16_t Size, uint32_t Timeout)
{
/* Step 1: Wait until BUSY flag is reset */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_BUSYF, SET, I2C_EVT_CHECK_NONE, I2C_TIMEOUT_BUSY_FLAG) != I2C_OK)
{
return I2C_ERROR_STEP_1;
}
/* Disable Pos */
I2C_NACKPositionConfig(I2Cx, I2C_NACKPosition_Current);
/* Enable Acknowledge */
I2C_AcknowledgeConfig(I2Cx, ENABLE);
/* Send START condition */
I2C_GenerateSTART(I2Cx, ENABLE);
/* Wait until SB flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_STARTF, RESET, I2C_EVT_CHECK_NONE, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_2;
}
/* Send slave address for write */
I2C_Send7bitAddress(I2Cx, DevAddress, I2C_Direction_Receive);
/* Wait until ADDR flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_ADDRF, RESET, I2C_EVT_CHECK_ACKFAIL, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_3;
}
if(Size == 1)
{
/* Disable Acknowledge */
I2C_AcknowledgeConfig(I2Cx, DISABLE);
/* Clear ADDR flag */
I2C_ClearADDRFlag(I2Cx);
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
}
else if(Size == 2)
{
/* Enable Pos */
I2C_NACKPositionConfig(I2Cx, I2C_NACKPosition_Next);
/* Disable Acknowledge */
I2C_AcknowledgeConfig(I2Cx, DISABLE);
/* Clear ADDR flag */
I2C_ClearADDRFlag(I2Cx);
}
else
{
/* Enable Acknowledge */
I2C_AcknowledgeConfig(I2Cx, ENABLE);
/* Clear ADDR flag */
I2C_ClearADDRFlag(I2Cx);
}
while(Size > 0)
{
if(Size <= 3)
{
/* One byte */
if(Size == 1)
{
/* Wait until RXNE flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_RDNE, RESET, I2C_EVT_CHECK_NONE, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_4;
}
/* Read data from DR */
(*pData++) = I2C_ReceiveData(I2Cx);
Size--;
}
/* Two bytes */
else if(Size == 2)
{
/* Wait until BTF flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_BTFF, RESET, I2C_EVT_CHECK_NONE, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_5;
}
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
/* Read data from DR */
(*pData++) = I2C_ReceiveData(I2Cx);
Size--;
/* Read data from DR */
(*pData++) = I2C_ReceiveData(I2Cx);
Size--;
}
/* 3 Last bytes */
else
{
/* Wait until BTF flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_BTFF, RESET, I2C_EVT_CHECK_NONE, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_6;
}
/* Disable Acknowledge */
I2C_AcknowledgeConfig(I2Cx, DISABLE);
/* Read data from DR */
(*pData++) = I2C_ReceiveData(I2Cx);
Size--;
/* Wait until BTF flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_BTFF, RESET, I2C_EVT_CHECK_NONE, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_7;
}
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
/* Read data from DR */
(*pData++) = I2C_ReceiveData(I2Cx);
Size--;
/* Read data from DR */
(*pData++) = I2C_ReceiveData(I2Cx);
Size--;
}
}
else
{
/* Wait until RXNE flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_RDNE, RESET, I2C_EVT_CHECK_NONE, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_8;
}
/* Read data from DR */
(*pData++) = I2C_ReceiveData(I2Cx);
Size--;
}
}
return I2C_OK;
}
/**
* @brief Transmits in master mode an amount of data in blocking mode.
* @param I2Cx: where x can be 1, 2 or 3 to select the I2C peripheral.
* @param DevAddress Target device address.
* @param pData Pointer to data buffer.
* @param Size Amount of data to be sent.
* @param Timeout Timeout duration.
* @retval I2C status.
*/
I2C_StatusType I2C_Transmit(I2C_Type* I2Cx, uint16_t DevAddress, uint8_t *pData, uint16_t Size, uint32_t Timeout)
{
/* Wait until BUSY flag is reset */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_BUSYF, SET, I2C_EVT_CHECK_NONE, I2C_TIMEOUT_BUSY_FLAG) != I2C_OK)
{
return I2C_ERROR_STEP_1;
}
/* Disable Pos */
I2C_NACKPositionConfig(I2Cx, I2C_NACKPosition_Current);
/* Send START condition */
I2C_GenerateSTART(I2Cx, ENABLE);
/* Wait until SB flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_STARTF, RESET, I2C_EVT_CHECK_NONE, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_2;
}
/* Send address for write */
I2C_Send7bitAddress(I2Cx, DevAddress, I2C_Direction_Transmit);
/* Wait until ADDR flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_ADDRF, RESET, I2C_EVT_CHECK_ACKFAIL, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_3;
}
/* Clear ADDR flag */
I2C_ClearADDRFlag(I2Cx);
while(Size > 0)
{
/* Wait until TDE flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_TDE, RESET, I2C_EVT_CHECK_ACKFAIL, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_4;
}
/* Write data to DR */
I2C_SendData(I2Cx, (*pData++));
Size--;
}
/* Wait until BTF flag is set */
if(I2C_WaitOnFlagUntilTimeout(I2Cx, I2C_FLAG_BTFF, RESET, I2C_EVT_CHECK_ACKFAIL, Timeout) != I2C_OK)
{
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_ERROR_STEP_5;
}
/* Send STOP Condition */
I2C_GenerateSTOP(I2Cx, ENABLE);
return I2C_OK;
}
/**
* @}
*/
/**
* @}
*/
懒得写，直接拷的例程中的代码，封装了发送和接收函数（有点想念HAL库了）
/* Define to prevent recursive inclusion -------------------------------------*/
#ifndef __AT32F4XX_I2C_EX_H
#define __AT32F4XX_I2C_EX_H
/* Includes ------------------------------------------------------------------*/
#include "at32f4xx.h"
/**
* @brief I2C Status structures definition
*/
typedef enum
{
I2C_OK = 0,
I2C_ERROR_STEP_1 = 1,
I2C_ERROR_STEP_2 = 2,
I2C_ERROR_STEP_3 = 3,
I2C_ERROR_STEP_4 = 4,
I2C_ERROR_STEP_5 = 5,
I2C_ERROR_STEP_6 = 6,
I2C_ERROR_STEP_7 = 7,
I2C_ERROR_STEP_8 = 8,
I2C_ERROR_STEP_9 = 9,
I2C_ERROR_STEP_10 = 10,
I2C_ERROR_STEP_11 = 11,
I2C_ERROR_STEP_12 = 12,
I2C_BUSY = 100,
I2C_TIMEOUT = 101,
I2C_ERROR = 102,
} I2C_StatusType;
/**
* @}
*/
/* Exported constants --------------------------------------------------------*/
/** @defgroup I2C_Exported_Constants I2C Exported Constants
* @{
*/
/**
* @brief I2C Parameter definition
*/
#define I2C_SPEED 100000
#define I2C_SLAVE_ADDRESS7 0xB0
#define I2C_EEAddress 0xB0
/**
* @brief I2C Interface pins
*/
#define I2C_PORT I2C1
#define I2C_CLK RCC_APB1PERIPH_I2C1
#define I2C_SCL_PIN GPIO_Pins_8 /* PB.8 */
#define I2C_SCL_GPIO_PORT GPIOB /* GPIOB */
#define I2C_GPIO_CLK RCC_AHBPERIPH_GPIOB
#define I2C_SCL_GPIO_PinsSource GPIO_PinsSource8
#define I2C_SCL_GPIO_GPIO_AF GPIO_AF_1
#define I2C_SDA_PIN GPIO_Pins_9 /* PB.9*/
#define I2C_SDA_GPIO_PORT GPIOB /* GPIOB */
#define I2C_SDA_GPIO_PinsSource GPIO_PinsSource9
#define I2C_SDA_GPIO_GPIO_AF GPIO_AF_1
/**
* @}
*/
/* Exported macro ------------------------------------------------------------*/
/** @defgroup I2C_Exported_Macros I2C Exported Macros
* @{
*/
#define MASTER_BOARD
/**
* @}
*/
/* Exported variables ------------------------------------------------------- */
/* Exported functions ------------------------------------------------------- */
/** @addtogroup I2C_Exported_Functions
* @{
*/
void I2Cx_Init(void);
I2C_StatusType I2C_Receive (I2C_Type* I2Cx, uint16_t DevAddress, uint8_t *pData, uint16_t Size, uint32_t Timeout);
I2C_StatusType I2C_Transmit(I2C_Type* I2Cx, uint16_t DevAddress, uint8_t *pData, uint16_t Size, uint32_t Timeout);
/**
* @}
*/
#endif /* __I2C_H */
还要新建CH450.c和。h文件来写ch450的驱动
#include "CH450.h"
#include "at32f4xx.h"
#include "drv_i2c.h"
#include <rtthread.h>
I2C_StatusType I2C_Status;
void CH450_Write(uint8_t cmd) //写参数
{
I2C_Status = I2C_Transmit(I2C_PORT, CH450_Write_ADDR, &cmd, 1, 1000);
rt_kprintf("I2C_Status:%d\r\n",I2C_Status);
}
unsigned char CH450_Read(void) //读取按键
{
unsigned char keycode;
I2C_Receive(I2C_PORT, CH450_Read_ADDR, &keycode, 1, 1000);
return(keycode);
}
void CH450_Init(void) //初始化
{
CH450_Write(CH450_SYSON2); //只开启按键
}
#ifndef __CH450_H
#define __CH450_H
#include "stdint.h"
/*
* 命令字节参数设定
*
* D7 D6 D5 D4 D3 D2 D1 D0
* SLEEP INTENS 0 0 0 KEYB DISP
*
* 设置系统参数命令用于设定 CH450 的系统级参数：显示驱动使能 DISP、键盘扫描使能 KEYB、显示驱动亮度控制 INTENS、低功耗睡眠控制 SLEEP。
*
* SLEEP 用于使 CH450 进入低功耗睡眠状态，从而可以节约电能。处于低功耗睡眠状态中的 CH450
*可以被下述两种事件中的任何一种唤醒，第一种事件是检测到 SEG3～SEG0 上的按键，有效按键代码
*是 42H 到 5FH；第二种事件是接收到单片机发出的下一个操作命令。当 CH450 被唤醒后，SLEEP 位会
*自动清 0。睡眠和唤醒操作本身不会影响 CH450 的其它工作状态。如果 KEYB 位为 1 则唤醒后产生按
*键中断，如果 KEYB 位为 0 则唤醒后不产生按键中断。
*
* INTENS 用于控制显示驱动的亮度，包含两位数据，有 4 种组合：数据 00、01、10 分别设置
*显示驱动占空比为 4/4、1/4、2/4，并且启用内部的段驱动限流；数据 11 设置显示驱动占空比为 4/4，
*但是禁止内部的段驱动限流，所以外部需要在段引脚串接限流电阻 R0。
*
* 当 KEYB 位为 1 时启用键盘扫描，当 KEYB 位为 0 时关闭键盘扫描。
*
* 当 DISP 位为 1 时允许显示输出，当 DISP 位为 0 时关闭显示驱动.
*/
/* CH450的常用命令码，如果考虑与I2C兼容，那么高8位应该右移1位 */
#define CH450_SYSOFF 0x00 // 关闭显示、关闭键盘
#define CH450_SYSON1 0x01 // 开启显示
#define CH450_SYSON2 0x03 // 开启显示、键盘
#define CH450_SYSON3 0x22 // 关闭显示、开启键盘
#define CH450_GET_KEY 0x0700 // 获取按键,返回按键代码
#define CH450_DIG2 0x1200 // 数码管位2显示,需另加8位数据
#define CH450_DIG3 0x1300 // 数码管位3显示,需另加8位数据
#define CH450_DIG4 0x1400 // 数码管位4显示,需另加8位数据
#define CH450_DIG5 0x1500 // 数码管位5显示,需另加8位数据
#define CH450_DIG6 0x1600 // 数码管位6显示,需另加8位数据
#define CH450_DIG7 0x1700 // 数码管位7显示,需另加8位数据
// CH450地址定义
#define CH450_Write_ADDR 0x48 // 设置命令地址
#define CH450_Read_ADDR 0x4F // 读取按键地址
#define CH450_DIG2_ADDR 0x64 // DIG2字命令
#define CH450_DIG3_ADDR 0x66 // DIG3字命令
#define CH450_DIG4_ADDR 0x68 // DIG4字命令
#define CH450_DIG5_ADDR 0x6A // DIG5字命令
#define CH450_DIG6_ADDR 0x6C // DIG6字命令
#define CH450_DIG7_ADDR 0x6E // DIG7字命令
unsigned char CH450_Read(void); // 从CH450读取按键代码
void CH450_Write(uint8_t cmd); // 向CH450发出操作命令
void CH450_Init(void); //初始化
#endif
main中创建线程之后延时1秒让CH450稳定复位
int main(void)
{
/* 创建ADC线程 */
ADC_thread = rt_thread_create("ADC", /* 线程名字 */
ADC_thread_entry, /* 线程入口函数 */
RT_NULL, /* 线程入口函数参数 */
sizeof(ADC_stack), /* 线程栈大小 */
4, /* 线程的优先级 */
10); /* 线程时间片 */
/* 启动线程，开启调度 */
if (ADC_thread != RT_NULL)
rt_thread_startup(ADC_thread);
/*CH450复位延时*/
rt_thread_mdelay(1000);
/*只开启按键扫描*/
CH450_Write(0x22);
return 0;
}
线程中定期读取按键编码，rt_kprintf貌似也不能输出十六进制，就先输出十进制先验证下功能吧！
static void ADC_thread_entry(void *parameter)
{
while (1)
{
if(ADC_GetINTStatus(ADC1, ADC_INT_EC) != RESET){
ADC_value = ADC_GetConversionValue(ADC1)*3.3f/4095;//ADC值转电压值
OLED_Showdecimal(10,10,ADC_value,2,3,16);、、OLED刷屏
OLED_Refresh();
ADC_SoftwareStartConvCtrl(ADC1, ENABLE);/* 启动ADC转换 */
}
rt_kprintf("KEY_Val:%d\r\n",CH450_Read());//十进制打印按键值
rt_thread_mdelay(300);
}
}
按下不同的按键可以看到打印值的改变，
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