硬件IIC的主从中断在582的最新EVT中已支持。
例程中已封装好中断处理过程，用户调用app_i2c时，初始化中需要配置回调函数即可。若需要串口打印日志，可以在工程预编译中增加宏CONFIG_I2C_DEBUG。
接下来以注释的方式解析一下中断服务函数中做了哪些处理。
__INTERRUPT
__HIGH_CODE
void I2C_IRQHandler(void)
{
uint32_t event = I2C_GetLastEvent();
print_i2c_irq_sta(event);
/* I2C Master */
if (event & (RB_I2C_MSL << 16)) { //判断为主机模式
if (event & RB_I2C_SB) { //判断主机模式已发送起始信号
/* Start condition sent, send address */
I2C_SendData(i2c_slave_addr_rw); //写从地址到数据寄存器后，SB位会自动清除
I2C_DBG("Master selected, send address\n");
}
/* I2C Master transmitter */
if (event & (RB_I2C_TRA << 16)) { //判断是主机的发送模式
I2C_DBG("Master transmitter:\n");
/* Slave receiver acked address or sent bit */
if (event & (RB_I2C_ADDR | RB_I2C_BTF | RB_I2C_TxE | (RB_I2C_TRA << 16))) {
/* if there is data to send, send it, otherwise stop */
if (i2c_master_buffer_index < i2c_master_buffer_length) { //判断待发送数据还没发完
I2C_SendData(i2c_master_buffer[i2c_master_buffer_index++]);
I2C_DBG(" send (%#x)\n",
i2c_master_buffer[i2c_master_buffer_index - 1]);
} else {
if (i2c_send_stop) { //判断数据发完了，如果允许产生停止位则产生停止位
i2c_state = I2C_READY;
I2C_GenerateSTOP(ENABLE); //产生停止位
I2C_DBG(" send STOP\n");
} else {
i2c_in_repstart = true; //置标志表示即将重起始
/* we're gonna send the START, don't enable the interrupt. */
I2C_ITConfig(I2C_IT_BUF, DISABLE);
I2C_ITConfig(I2C_IT_EVT, DISABLE);
I2C_ITConfig(I2C_IT_ERR, DISABLE);
I2C_GenerateSTART(ENABLE);
i2c_state = I2C_READY;
I2C_DBG(" restart\n");
}
}
}
/* Address or data sent, nack received */
if (event & RB_I2C_AF) { //地址/数据发送后应答失败
I2C_ClearFlag(I2C_FLAG_AF); //清标志
i2c_error = I2C_MT_NACK; //置主机发送接收错误标志
i2c_state = I2C_READY; //发送停止信号停止帧传输
I2C_GenerateSTOP(ENABLE); //产生停止信号
I2C_DBG(" NACK received, sent stop\n");
}
} else { //判断是主机的接收模式
/* I2C Master reveiver */
I2C_DBG("Master receiver:\n");
/* address sent, ack received */
if(event & RB_I2C_ADDR) { //主机成功设置了从机的地址
/* ack if more bytes are expected, otherwise nack */
if (i2c_master_buffer_index + 1 < i2c_master_buffer_length) { //判断接下来需要接收多少字节，如果需要接收多个字节，就置自动回ACK
I2C_AcknowledgeConfig(ENABLE);
I2C_DBG(" address sent\n");
I2C_DBG(" ACK next\n");
} else { //判断接下来只接收一个字节，关闭自动回ACK即自动回NACK
//XXX: Should not delay too match before NACK
I2C_AcknowledgeConfig(DISABLE);
is_nack_sent = true; //置标志，数据接收时做具体处理
I2C_DBG(" address sent\n");
I2C_DBG(" NACK next\n");
}
}
/* data reveived */
if (event & (RB_I2C_RxNE)) { //接收数据寄存器内非空，即收到数据
/* put byte into buffer */
i2c_master_buffer[i2c_master_buffer_index++] = I2C_ReceiveData(); //接收数据到buffer中
if (i2c_master_buffer_index < i2c_master_buffer_length) { //判断接下来是否为期望接收的最后一个字节
I2C_AcknowledgeConfig(ENABLE); //接下来不是最后一个字节，接收应答设置为自动回ACK
I2C_DBG(" ACK next\n");
} else {
//XXX: Should not delay too match before NACK
I2C_AcknowledgeConfig(DISABLE); //连续读倒数最后一个字节前将接收应答ACK关闭，即最后一个字节后自动回NACK
I2C_DBG(" NACK next\n");
if (is_nack_sent) { //如果已设置最后一个字节前置了接收应答NACK
is_nack_sent = false; //清标志
if (i2c_send_stop) {
I2C_GenerateSTOP(ENABLE);
i2c_state = I2C_READY;
I2C_DBG(" send STOP\n");
} else {
i2c_in_repstart = true; //写完了从机内的目标寄存器，发重起始信号
/* we're gonna send the START, don't enable the interrupt. */
I2C_ITConfig(I2C_IT_BUF, DISABLE);
I2C_ITConfig(I2C_IT_EVT, DISABLE);
I2C_ITConfig(I2C_IT_ERR, DISABLE);
I2C_GenerateSTART(ENABLE);
i2c_state = I2C_READY;
I2C_DBG(" restart\n");
}
} else {
is_nack_sent = true; //没有要求
}
}
I2C_DBG(" received data (%#x)\n",
i2c_master_buffer[i2c_master_buffer_index - 1]);
}
/* nack received */
if (event & RB_I2C_AF) { //主机接收模式最后一个字节后为NACK
I2C_ClearFlag(I2C_FLAG_AF);
/* put final byte into buffer */
i2c_master_buffer[i2c_master_buffer_index++] = I2C_ReceiveData(); //收下最后一个字节的数据
if (i2c_send_stop) { //判断读完之后是停止信号还是重起始信号
i2c_state = I2C_READY;
I2C_GenerateSTOP(ENABLE);
I2C_DBG(" NACK received, send STOP\n");
} else {
i2c_in_repstart = true; //读完后不停止，会产生重起始信号以衔接后续操作
/* we're gonna send the START, don't enable the interrupt. */
I2C_ITConfig(I2C_IT_BUF, DISABLE);
I2C_ITConfig(I2C_IT_EVT, DISABLE);
I2C_ITConfig(I2C_IT_ERR, DISABLE);
I2C_GenerateSTART(ENABLE);
i2c_state = I2C_READY;
I2C_DBG(" restart\n");
}
}
}
} else { //判断为从机模式
/* I2C slave */
/* addressed, returned ack */
if (event & RB_I2C_ADDR) { //地址匹配，接下来判断方向
if (event & ((RB_I2C_TRA << 16) | RB_I2C_TxE)) { //判断从机发送方向匹配或者发送方向寄存器空，那么接下来需要发送数据 //发送方向寄存器空需要判断吗？
I2C_DBG("Slave transmitter address matched\n");
i2c_state = I2C_STX;
i2c_slave_txbuffer_index = 0;
i2c_slave_txbuffer_length = 0;
if (slave_cb && slave_cb->on_transmit) { //如果注册了回调，就按照回调函数，将数据拷贝到i2c_slave_txbuffer中
slave_cb->on_transmit(i2c_slave_txbuffer, &i2c_slave_txbuffer_length);
}
} else { //判断从机接收方向地址匹配，那么接下来需要接收数据
I2C_DBG("Slave reveiver address matched\n");
i2c_state = I2C_SRX;
i2c_slave_rxbuffer_index = 0;
}
}
if (event & (RB_I2C_TRA << 16)) { //从机发送
/* Slave transmintter */
I2C_AcknowledgeConfig(ENABLE); //预设自动回复ACK
I2C_DBG("Slave transmitter:\n");
if (event & RB_I2C_AF) { //收到了NACK，发送失败
/* Nack received */
I2C_ClearFlag(I2C_FLAG_AF); //清除应答失败标志
I2C_AcknowledgeConfig(ENABLE); //预设自动回复ACK
I2C_DBG(" Nack received\n");
/* leave slave receiver state */
i2c_state = I2C_READY;
/* clear status */
event = 0;
}
if(event & (RB_I2C_BTF | RB_I2C_TxE)) { //字节发送结束或者发送方向寄存器空
/* copy data to output register */
I2C_SendData(i2c_slave_txbuffer[i2c_slave_txbuffer_index++]); //逐字节发送数据
/* if there is more to send, ack, otherwise nack */
if (i2c_slave_txbuffer_index < i2c_slave_txbuffer_length) {
I2C_AcknowledgeConfig(ENABLE); //预设自动回复ACK
}else{
I2C_AcknowledgeConfig(DISABLE); //预设自动回复NACK
}
I2C_DBG(" send (%#x)\n",
i2c_slave_txbuffer[i2c_slave_txbuffer_index - 1]);
}
} else { //从机接收
/* Slave receiver */
I2C_DBG("Slave receiver:\n");
if (event & RB_I2C_RxNE) { //判断非空即收到了数据
/* if there is still room in the rx buffer */
//判断还有没有缓存空间，如果仍有空间就接收数据并回ACK，没有更多空间了就回NACK
if (i2c_slave_rxbuffer_index < I2C_BUFFER_LENGTH) {
/* put byte in buffer and ack */
i2c_slave_rxbuffer[i2c_slave_rxbuffer_index++] = I2C_ReceiveData();
I2C_AcknowledgeConfig(ENABLE);
I2C_DBG(" received (%#x)\n",
i2c_slave_rxbuffer[i2c_slave_rxbuffer_index - 1]);
} else {
// otherwise nack
I2C_AcknowledgeConfig(DISABLE);
}
}
if (event & RB_I2C_STOPF) { //从机接收模式下收到停止位，清标志，清数组下标索引
/* ack future responses and leave slave receiver state */
R16_I2C_CTRL1 |= RB_I2C_PE; //clear flag
I2C_DBG(" reveive stop\n");
/* callback to user defined callback */
if (slave_cb && slave_cb->on_receive) {
slave_cb->on_receive(i2c_slave_rxbuffer, i2c_slave_rxbuffer_index);
}
/* since we submit rx buffer , we can reset it */
i2c_slave_rxbuffer_index = 0;
}
if (event & RB_I2C_AF) { //如果接收模式中接收到了NACK，清标志，预设自动回复ACK
I2C_ClearFlag(I2C_FLAG_AF);
/* ack future responses */
I2C_AcknowledgeConfig(ENABLE);
}
}
}
if(event & RB_I2C_BERR){ //总线错误
I2C_ClearFlag(RB_I2C_BERR);
I2C_GenerateSTOP(ENABLE);
i2c_error = I2C_BUS_ERROR;
I2C_DBG("RB_I2C_BERR\n");
}
if(event & RB_I2C_ARLO){ //仲裁丢失错误
I2C_ClearFlag(RB_I2C_ARLO);
i2c_error = I2C_ARB_LOST;
I2C_DBG("RB_I2C_ARLO\n");
}
I2C_DBG("\n");
}
标签：解析,slave,IIC,DBG,event,RB,I2C,主从,i2c From： https://www.cnblogs.com/JayWellsBlog/p/16917961.html