360 lines
8.3 KiB
C
360 lines
8.3 KiB
C
/*
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* Copyright (c) 2006-2018, RT-Thread Development Team
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Change Logs:
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* Date Author Notes
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* 2017-09-06 勤为本 first version
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*/
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// 封装硬件i2c接口
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#include "ls1c_public.h"
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#include "ls1c_regs.h"
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#include "ls1c_clock.h"
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#include "ls1c_i2c.h"
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#include "ls1c_delay.h"
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/*
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* I2C各个寄存器相对基地址的偏移
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* 发送数据寄存器和接收数据寄存器的偏移是相同的
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* 命令寄存器和状态寄存器的偏移是相同的，不同的是命令寄存器只写，状态寄存器只读
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*/
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#define LS1C_I2C_PRER_LOW_OFFSET (0) // 分频锁存器低字节寄存器偏移
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#define LS1C_I2C_PRER_HIGH_OFFSET (1) // 分频锁存器高字节寄存器偏移
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#define LS1C_I2C_CONTROL_OFFSET (2) // 控制寄存器偏移
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#define LS1C_I2C_DATA_OFFSET (3) // 发送数据寄存器和接收数据寄存器的偏移是相同的
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#define LS1C_I2C_CMD_OFFSET (4) // 命令寄存器偏移，只写
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#define LS1C_I2C_STATUS_OFFSET (4) // 状态寄存器偏移，只读
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// 控制寄存器的位域
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#define LS1C_I2C_CONTROL_EN (0x80) // i2c模块使能
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#define LS1C_I2C_CONTROL_IEN (0x40) // 中断使能
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// 命令寄存器的位域
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#define LS1C_I2C_CMD_START (0x90) // 产生START信号
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#define LS1C_I2C_CMD_STOP (0x40) // 产生STOP信号
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#define LS1C_I2C_CMD_READ (0x20) // 产生读信号，即产生ACK信号
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#define LS1C_I2C_CMD_WRITE (0x10) // 产生写信号
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#define LS1C_I2C_CMD_READ_ACK (0x20) // 产生ACK信号，与读信号相同
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#define LS1C_I2C_CMD_READ_NACK (0x28) // 产生NACK信号
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#define LS1C_I2C_CMD_IACK (0x00) // 产生中断应答信号
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// 状态寄存器的位域
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#define LS1C_I2C_STATUS_IF (0x01) // 中断标志位
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#define LS1C_I2C_STATUS_TIP (0x02) // 指示传输的过程。1，正在传输；0，传输完成
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#define LS1C_I2C_STATUS_ARBLOST (0x20) // I2C核失去I2C总线的控制权
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#define LS1C_I2C_STATUS_BUSY (0x40) // I2C总线忙标志
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#define LS1C_I2C_STATUS_NACK (0x80) // 应答位标志。1，没收到应答位；0，收到应答位
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/*
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* 获取指定i2c模块的基地址
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* @I2Cx I2C模块的编号
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*/
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void *i2c_get_base(ls1c_i2c_t I2Cx)
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{
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void *base = NULL;
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switch (I2Cx)
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{
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case LS1C_I2C_0:
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base = (void *)LS1C_I2C0_BASE;
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break;
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case LS1C_I2C_1:
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base = (void *)LS1C_I2C1_BASE;
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break;
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case LS1C_I2C_2:
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base = (void *)LS1C_I2C2_BASE;
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break;
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default:
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base = NULL;
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break;
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}
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return base;
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}
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/*
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* 向命令寄存器写命令
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* @i2c_info_p i2c模块信息
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* @cmd 命令
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*/
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void i2c_cmd(ls1c_i2c_info_t *i2c_info_p, unsigned char cmd)
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{
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void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
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reg_write_8(cmd, i2c_base + LS1C_I2C_CMD_OFFSET);
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return ;
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}
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/*
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* 执行START命令，发送START信号
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* @i2c_info_p i2c模块信息
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*/
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void i2c_cmd_start(ls1c_i2c_info_t *i2c_info_p)
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{
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i2c_cmd(i2c_info_p, LS1C_I2C_CMD_START);
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return ;
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}
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/*
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* 执行STOP命令，发送STOP信号
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* @i2c_info_p i2c模块信息
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*/
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void i2c_cmd_stop(ls1c_i2c_info_t *i2c_info_p)
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{
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i2c_cmd(i2c_info_p, LS1C_I2C_CMD_STOP);
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return ;
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}
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/*
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* 执行写命令
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* @i2c_info_p i2c模块信息
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*/
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void i2c_cmd_write(ls1c_i2c_info_t *i2c_info_p)
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{
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i2c_cmd(i2c_info_p, LS1C_I2C_CMD_WRITE);
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return ;
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}
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/*
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* 执行读ack命令，发送读ack信号
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* @i2c_info_p i2c模块信息
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*/
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void i2c_cmd_read_ack(ls1c_i2c_info_t *i2c_info_p)
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{
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i2c_cmd(i2c_info_p, LS1C_I2C_CMD_READ_ACK);
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return ;
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}
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/*
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* 执行读nack命令,发送读nack信号
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* @i2c_info_p i2c模块信息
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*/
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void i2c_cmd_read_nack(ls1c_i2c_info_t *i2c_info_p)
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{
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i2c_cmd(i2c_info_p, LS1C_I2C_CMD_READ_NACK);
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return ;
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}
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/*
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* 发送中断应答信号
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* @i2c_info_p i2c模块信息
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*/
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void i2c_cmd_iack(ls1c_i2c_info_t *i2c_info_p)
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{
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i2c_cmd(i2c_info_p, LS1C_I2C_CMD_IACK);
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return ;
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}
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/*
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* 获取状态寄存器的值
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* @i2c_info_p i2c模块信息
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* @ret 状态寄存器的值
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*/
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unsigned char i2c_get_status(ls1c_i2c_info_t *i2c_info_p)
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{
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void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
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return reg_read_8(i2c_base + LS1C_I2C_STATUS_OFFSET);
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}
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/*
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* Poll the i2c status register until the specified bit is set.
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* Returns 0 if timed out (100 msec).
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* @i2c_info_p i2c模块信息
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* @bit 寄存器的某一位
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* @ret true or false
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*/
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int i2c_poll_status(ls1c_i2c_info_t *i2c_info_p, unsigned long bit)
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{
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int loop_cntr = 20000;
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do {
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delay_us(1);
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} while ((i2c_get_status(i2c_info_p) & bit) && (0 < --loop_cntr));
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return (0 < loop_cntr);
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}
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/*
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* 初始化指定i2c模块
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* @i2c_info_p 某个i2c模块的信息
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*/
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void i2c_init(ls1c_i2c_info_t *i2c_info_p)
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{
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void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
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unsigned long i2c_clock = i2c_info_p->clock;
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unsigned char ctrl = reg_read_8(i2c_base + LS1C_I2C_CONTROL_OFFSET);
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unsigned long prescale = 0;
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/* make sure the device is disabled */
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ctrl = ctrl & ~(LS1C_I2C_CONTROL_EN | LS1C_I2C_CONTROL_IEN);
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reg_write_8(ctrl, i2c_base + LS1C_I2C_CONTROL_OFFSET);
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// 设置时钟
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i2c_clock = MIN(i2c_clock, LS1C_I2C_CLOCK_MAX); // 限制在最大允许范围内
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prescale = clk_get_apb_rate();
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prescale = (prescale / (5 * i2c_clock)) - 1;
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reg_write_8(prescale & 0xff, i2c_base + LS1C_I2C_PRER_LOW_OFFSET);
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reg_write_8(prescale >> 8, i2c_base + LS1C_I2C_PRER_HIGH_OFFSET);
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// 使能
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i2c_cmd_iack(i2c_info_p);
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ctrl = ctrl | LS1C_I2C_CONTROL_EN;
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reg_write_8(ctrl, i2c_base + LS1C_I2C_CONTROL_OFFSET);
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return ;
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}
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/*
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* (再发送一个字节数据之后)接收从机发送的ACK信号
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* @i2c_info_p i2c模块信息
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* @ret LS1C_I2C_ACK or LS1C_I2C_NACK
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*/
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ls1c_i2c_ack_t i2c_receive_ack(ls1c_i2c_info_t *i2c_info_p)
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{
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ls1c_i2c_ack_t ret = LS1C_I2C_NACK;
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if (LS1C_I2C_STATUS_NACK & i2c_get_status(i2c_info_p))
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{
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ret = LS1C_I2C_NACK;
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}
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else
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{
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ret = LS1C_I2C_ACK;
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}
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return ret;
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}
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/*
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* 接收数据
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* @i2c_info_p i2c模块信息
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* @buf 数据缓存
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* @len 待接收数据的长度
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*/
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ls1c_i2c_ret_t i2c_receive_data(ls1c_i2c_info_t *i2c_info_p, unsigned char *buf, int len)
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{
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void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
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int i = 0;
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for (i=0; i<len; i++)
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{
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// 开始接收
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if (i != (len - 1))
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i2c_cmd_read_ack(i2c_info_p);
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else
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i2c_cmd_read_nack(i2c_info_p);
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// 等待，直到接收完成
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if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_TIP))
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return LS1C_I2C_RET_TIMEOUT;
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// 读取数据，并保存
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*buf++ = reg_read_8(i2c_base + LS1C_I2C_DATA_OFFSET);
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}
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return LS1C_I2C_RET_OK;
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}
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/*
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* 发送START信号和地址
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* @i2c_info_p i2c模块信息
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* @slave_addr 从机地址
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* @direction 数据传输方向(读、写)
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*/
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ls1c_i2c_ret_t i2c_send_start_and_addr(ls1c_i2c_info_t *i2c_info_p,
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unsigned char slave_addr,
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ls1c_i2c_direction_t direction)
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{
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void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
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unsigned char data = 0;
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// 等待i2c总线空闲
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if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_BUSY))
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return LS1C_I2C_RET_TIMEOUT;
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// 填充地址到数据寄存器
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data = (slave_addr << 1) | ((LS1C_I2C_DIRECTION_READ == direction) ? 1 : 0);
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reg_write_8(data , i2c_base + LS1C_I2C_DATA_OFFSET);
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// 开始发送
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i2c_cmd_start(i2c_info_p);
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// 等待，直到发送完成
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if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_TIP))
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return LS1C_I2C_RET_TIMEOUT;
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return LS1C_I2C_RET_OK;
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}
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/*
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* 发送数据
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* @i2c_info_p i2c模块信息
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* @data 待发送的数据
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* @len 待发送数据的长度
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*/
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ls1c_i2c_ret_t i2c_send_data(ls1c_i2c_info_t *i2c_info_p, unsigned char *data, int len)
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{
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void *i2c_base = i2c_get_base(i2c_info_p->I2Cx);
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int i = 0;
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for (i=0; i<len; i++)
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{
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// 将一个字节数据写入数据寄存器
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reg_write_8(*data++, i2c_base + LS1C_I2C_DATA_OFFSET);
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// 开始发送
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reg_write_8(LS1C_I2C_CMD_WRITE, i2c_base + LS1C_I2C_CMD_OFFSET);
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// 等待，直到发送完成
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if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_TIP))
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return LS1C_I2C_RET_TIMEOUT;
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// 读取应答信号
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if (LS1C_I2C_ACK != i2c_receive_ack(i2c_info_p))
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return len;
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}
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return LS1C_I2C_RET_OK;
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}
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/*
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* 发送STOP信号
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* @i2c_info_p i2c模块信息
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*/
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void i2c_send_stop(ls1c_i2c_info_t *i2c_info_p)
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{
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i2c_cmd_stop(i2c_info_p);
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return ;
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}
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