/* * File : ls1c_i2c.c * This file is part of RT-Thread RTOS * COPYRIGHT (C) 2006 - 2012, RT-Thread Development Team * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. * * Change Logs: * Date Author Notes * 2017-09-06 勤为本 first version */ // 封装硬件i2c接口 #include "ls1c_public.h" #include "ls1c_regs.h" #include "ls1c_clock.h" #include "ls1c_i2c.h" #include "ls1c_delay.h" /* * I2C各个寄存器相对基地址的偏移 * 发送数据寄存器和接收数据寄存器的偏移是相同的 * 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 */ #define LS1C_I2C_PRER_LOW_OFFSET (0) // 分频锁存器低字节寄存器偏移 #define LS1C_I2C_PRER_HIGH_OFFSET (1) // 分频锁存器高字节寄存器偏移 #define LS1C_I2C_CONTROL_OFFSET (2) // 控制寄存器偏移 #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 #define LS1C_I2C_CMD_OFFSET (4) // 命令寄存器偏移，只写 #define LS1C_I2C_STATUS_OFFSET (4) // 状态寄存器偏移，只读 // 控制寄存器的位域 #define LS1C_I2C_CONTROL_EN (0x80) // i2c模块使能 #define LS1C_I2C_CONTROL_IEN (0x40) // 中断使能 // 命令寄存器的位域 #define LS1C_I2C_CMD_START (0x90) // 产生START信号 #define LS1C_I2C_CMD_STOP (0x40) // 产生STOP信号 #define LS1C_I2C_CMD_READ (0x20) // 产生读信号，即产生ACK信号 #define LS1C_I2C_CMD_WRITE (0x10) // 产生写信号 #define LS1C_I2C_CMD_READ_ACK (0x20) // 产生ACK信号，与读信号相同 #define LS1C_I2C_CMD_READ_NACK (0x28) // 产生NACK信号 #define LS1C_I2C_CMD_IACK (0x00) // 产生中断应答信号 // 状态寄存器的位域 #define LS1C_I2C_STATUS_IF (0x01) // 中断标志位 #define LS1C_I2C_STATUS_TIP (0x02) // 指示传输的过程。1，正在传输；0，传输完成 #define LS1C_I2C_STATUS_ARBLOST (0x20) // I2C核失去I2C总线的控制权 #define LS1C_I2C_STATUS_BUSY (0x40) // I2C总线忙标志 #define LS1C_I2C_STATUS_NACK (0x80) // 应答位标志。1，没收到应答位；0，收到应答位 /* * 获取指定i2c模块的基地址 * @I2Cx I2C模块的编号 */ void *i2c_get_base(ls1c_i2c_t I2Cx) { void *base = NULL; switch (I2Cx) { case LS1C_I2C_0: base = (void *)LS1C_I2C0_BASE; break; case LS1C_I2C_1: base = (void *)LS1C_I2C1_BASE; break; case LS1C_I2C_2: base = (void *)LS1C_I2C2_BASE; break; default: base = NULL; break; } return base; } /* * 向命令寄存器写命令 * @i2c_info_p i2c模块信息 * @cmd 命令 */ void i2c_cmd(ls1c_i2c_info_t *i2c_info_p, unsigned char cmd) { void *i2c_base = i2c_get_base(i2c_info_p->I2Cx); reg_write_8(cmd, i2c_base + LS1C_I2C_CMD_OFFSET); return ; } /* * 执行START命令，发送START信号 * @i2c_info_p i2c模块信息 */ void i2c_cmd_start(ls1c_i2c_info_t *i2c_info_p) { i2c_cmd(i2c_info_p, LS1C_I2C_CMD_START); return ; } /* * 执行STOP命令，发送STOP信号 * @i2c_info_p i2c模块信息 */ void i2c_cmd_stop(ls1c_i2c_info_t *i2c_info_p) { i2c_cmd(i2c_info_p, LS1C_I2C_CMD_STOP); return ; } /* * 执行写命令 * @i2c_info_p i2c模块信息 */ void i2c_cmd_write(ls1c_i2c_info_t *i2c_info_p) { i2c_cmd(i2c_info_p, LS1C_I2C_CMD_WRITE); return ; } /* * 执行读ack命令，发送读ack信号 * @i2c_info_p i2c模块信息 */ void i2c_cmd_read_ack(ls1c_i2c_info_t *i2c_info_p) { i2c_cmd(i2c_info_p, LS1C_I2C_CMD_READ_ACK); return ; } /* * 执行读nack命令,发送读nack信号 * @i2c_info_p i2c模块信息 */ void i2c_cmd_read_nack(ls1c_i2c_info_t *i2c_info_p) { i2c_cmd(i2c_info_p, LS1C_I2C_CMD_READ_NACK); return ; } /* * 发送中断应答信号 * @i2c_info_p i2c模块信息 */ void i2c_cmd_iack(ls1c_i2c_info_t *i2c_info_p) { i2c_cmd(i2c_info_p, LS1C_I2C_CMD_IACK); return ; } /* * 获取状态寄存器的值 * @i2c_info_p i2c模块信息 * @ret 状态寄存器的值 */ unsigned char i2c_get_status(ls1c_i2c_info_t *i2c_info_p) { void *i2c_base = i2c_get_base(i2c_info_p->I2Cx); return reg_read_8(i2c_base + LS1C_I2C_STATUS_OFFSET); } /* * Poll the i2c status register until the specified bit is set. * Returns 0 if timed out (100 msec). * @i2c_info_p i2c模块信息 * @bit 寄存器的某一位 * @ret true or false */ int i2c_poll_status(ls1c_i2c_info_t *i2c_info_p, unsigned long bit) { int loop_cntr = 20000; do { delay_us(1); } while ((i2c_get_status(i2c_info_p) & bit) && (0 < --loop_cntr)); return (0 < loop_cntr); } /* * 初始化指定i2c模块 * @i2c_info_p 某个i2c模块的信息 */ void i2c_init(ls1c_i2c_info_t *i2c_info_p) { void *i2c_base = i2c_get_base(i2c_info_p->I2Cx); unsigned long i2c_clock = i2c_info_p->clock; unsigned char ctrl = reg_read_8(i2c_base + LS1C_I2C_CONTROL_OFFSET); unsigned long prescale = 0; /* make sure the device is disabled */ ctrl = ctrl & ~(LS1C_I2C_CONTROL_EN | LS1C_I2C_CONTROL_IEN); reg_write_8(ctrl, i2c_base + LS1C_I2C_CONTROL_OFFSET); // 设置时钟 i2c_clock = MIN(i2c_clock, LS1C_I2C_CLOCK_MAX); // 限制在最大允许范围内 prescale = clk_get_apb_rate(); prescale = (prescale / (5 * i2c_clock)) - 1; reg_write_8(prescale & 0xff, i2c_base + LS1C_I2C_PRER_LOW_OFFSET); reg_write_8(prescale >> 8, i2c_base + LS1C_I2C_PRER_HIGH_OFFSET); // 使能 i2c_cmd_iack(i2c_info_p); ctrl = ctrl | LS1C_I2C_CONTROL_EN; reg_write_8(ctrl, i2c_base + LS1C_I2C_CONTROL_OFFSET); return ; } /* * (再发送一个字节数据之后)接收从机发送的ACK信号 * @i2c_info_p i2c模块信息 * @ret LS1C_I2C_ACK or LS1C_I2C_NACK */ ls1c_i2c_ack_t i2c_receive_ack(ls1c_i2c_info_t *i2c_info_p) { ls1c_i2c_ack_t ret = LS1C_I2C_NACK; if (LS1C_I2C_STATUS_NACK & i2c_get_status(i2c_info_p)) { ret = LS1C_I2C_NACK; } else { ret = LS1C_I2C_ACK; } return ret; } /* * 接收数据 * @i2c_info_p i2c模块信息 * @buf 数据缓存 * @len 待接收数据的长度 */ ls1c_i2c_ret_t i2c_receive_data(ls1c_i2c_info_t *i2c_info_p, unsigned char *buf, int len) { void *i2c_base = i2c_get_base(i2c_info_p->I2Cx); int i = 0; for (i=0; iI2Cx); unsigned char data = 0; // 等待i2c总线空闲 if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_BUSY)) return LS1C_I2C_RET_TIMEOUT; // 填充地址到数据寄存器 data = (slave_addr << 1) | ((LS1C_I2C_DIRECTION_READ == direction) ? 1 : 0); reg_write_8(data , i2c_base + LS1C_I2C_DATA_OFFSET); // 开始发送 i2c_cmd_start(i2c_info_p); // 等待，直到发送完成 if (!i2c_poll_status(i2c_info_p, LS1C_I2C_STATUS_TIP)) return LS1C_I2C_RET_TIMEOUT; return LS1C_I2C_RET_OK; } /* * 发送数据 * @i2c_info_p i2c模块信息 * @data 待发送的数据 * @len 待发送数据的长度 */ ls1c_i2c_ret_t i2c_send_data(ls1c_i2c_info_t *i2c_info_p, unsigned char *data, int len) { void *i2c_base = i2c_get_base(i2c_info_p->I2Cx); int i = 0; for (i=0; i