问答

GD32F103的IIC模块在进行eeprom读取的时候，当读取的字节数为2时，需要将I2C_CTL0的POAP置为1；POAP的定义如下： 0：ACKEN位决定对当前正在接收的字节发送ACK; 1: ACKEN位决定是否对下一个字节发送ACK. 我的理解时：当读取的字节数为2时，该位置1，表示接收第一个字节后，发送ACK;接收第二个字节后，不发送ACK。这样就能保证时序的正确性。 不知道各位大佬是如何理解的，请赐教。谢谢！ 代码如下： void eeprom_buffer_read(uint8_t* p_buffer, uint8_t read_address, uint16_t number_of_byte) { /* wait until I2C bus is idle */ while(i2c_flag_get(I2C0, I2C_FLAG_I2CBSY)); if(2 == number_of_byte) { i2c_ackpos_config(I2C0,I2C_ACKPOS_NEXT); //如果接收的的字节数等于2，则将将I2C_CTL0的POAP置为1。 } /* send a start condition to I2C bus */ i2c_start_on_bus(I2C0); /* wait until SBSEND bit is set */ while(!i2c_flag_get(I2C0, I2C_FLAG_SBSEND)); /* send slave address to I2C bus */ i2c_master_addressing(I2C0, eeprom_address, I2C_TRANSMITTER); /* wait until ADDSEND bit is set */ while(!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND)); /* clear the ADDSEND bit */ i2c_flag_clear(I2C0,I2C_FLAG_ADDSEND); /* wait until the transmit data buffer is empty */ while(SET != i2c_flag_get( I2C0 , I2C_FLAG_TBE)); /* enable I2C0*/ i2c_enable(I2C0); /* send the EEPROM's internal address to write to */ i2c_data_transmit(I2C0, read_address); /* wait until BTC bit is set */ while(!i2c_flag_get(I2C0, I2C_FLAG_BTC)); /* send a start condition to I2C bus */ i2c_start_on_bus(I2C0); /* wait until SBSEND bit is set */ while(!i2c_flag_get(I2C0, I2C_FLAG_SBSEND)); /* send slave address to I2C bus */ i2c_master_addressing(I2C0, eeprom_address, I2C_RECEIVER); if(number_of_byte < 3){ /* disable acknowledge */ i2c_ack_config(I2C0,I2C_ACK_DISABLE); } /* wait until ADDSEND bit is set */ while(!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND)); /* clear the ADDSEND bit */ i2c_flag_clear(I2C0,I2C_FLAG_ADDSEND); if(1 == number_of_byte){ /* send a stop condition to I2C bus */ i2c_stop_on_bus(I2C0); } /* while there is data to be read */ while(number_of_byte){ if(3 == number_of_byte){ /* wait until BTC bit is set */ while(!i2c_flag_get(I2C0, I2C_FLAG_BTC)); /* disable acknowledge */ i2c_ack_config(I2C0,I2C_ACK_DISABLE); } if(2 == number_of_byte){ /* wait until BTC bit is set */ while(!i2c_flag_get(I2C0, I2C_FLAG_BTC)); /* send a stop condition to I2C bus */ i2c_stop_on_bus(I2C0); } /* wait until the RBNE bit is set and clear it */ if(i2c_flag_get(I2C0, I2C_FLAG_RBNE)){ /* read a byte from the EEPROM */ *p_buffer = i2c_data_receive(I2C0); /* point to the next location where the byte read will be saved */ p_buffer++; /* decrement the read bytes counter */ number_of_byte--; } } /* wait until the stop condition is finished */ while(I2C_CTL0(I2C0)&0x0200); /* enable acknowledge */ i2c_ack_config(I2C0,I2C_ACK_ENABLE); i2c_ackpos_config(I2C0,I2C_ACKPOS_CURRENT); }