![codevisionavr debugger codevisionavr debugger](https://www.roboblock.co.kr/info/images/visi28.jpg)
Until now, we have seen a general introduction to serial communication, followed by a tutorial on the concepts of RS-232 communication. So here we are with the AVR communication protocols series, starting with the most basic ones, UART and USART! We will move on to SPI and TWI (I2C) later. Set PORRTB to equal eeprom_rd_data to display its value.Hey folks! Lets continue with our tutorials on Serial Communication. It will go into the variable eeprom_rd_data, since you passed the address of that variable into the function. So send the same struct, but only two bytes of it. When you read back the value, you only need to send the address of the byte to the EEPROM.
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You don't care about receiving right now, so just put in 0 and 0 for the address and length to receive. (unsigned char *) &twi_eeprom is the address of the struct. If you give the function the address of the struct and the length 3, the function will take care of it for you. To write 0x55 to the EEPROM at a specific address, you need to send three bytes to the EEPROM.
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The next two are the address of the buffer to put the received data into, and the length. The next two params are the address of the buffer to take data from and the length to take. The first parameter is a constant given in your code. The functions given in twi.h describe a way to start this process, and the parameters are described there. That is, a byte is transferred to the slave simultaneously to a byte being transferred back from the slave. The data moves between the devices at the same time.
CODEVISIONAVR DEBUGGER CODE
In your case, your code runs on the master, and the EEPROM is the slave. TWI is a method for transferring data both ways from a master device to a slave device. Twi_master_trans(EEPROM_TWI_BUS_ADDRESS,(unsigned char *) &twi_eeprom,2,&eeprom_rd_data,1) Ĭould someone please explain it? what does the &twi_eeprom,3,0,0 actually mean?Īny answer and comment would be appreciate. Twi_master_trans(EEPROM_TWI_BUS_ADDRESS,(unsigned char *) &twi_eeprom,3,0,0)
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slave_rx_handler - pointer to the TWI slave receive processing function tx_buffer - pointer to the slave transmit buffer rx_buffer_size - size of the slave receive buffer rx_buffer - pointer to the slave receive buffer match_any_addr - if true, the slave match address logic responds to all received addresses Unsigned char *rx_data, unsigned char rx_count) Unsigned char *tx_data, unsigned char tx_count, rx_count - number of bytes that must be received from the slave during the transaction rx_data - pointer to the buffer that holds the data received from the slave tx_count - number of bytes that must be transmitted to the slave during the transaction tx_data - pointer to the buffer that holds the data to be transmitted to the slave slave_addr - 7 bit address of the TWI slave with which the transaction must be performed function used for performing a TWI master transaction Void twi_master_init(unsigned int bit_rate) Function: Bit7=Out Bit6=Out Bit5=Out Bit4=Out Bit3=Out Bit2=Out Bit1=Out Bit0=OutĮxtern unsigned char twi_tx_index // data index in the transmit bufferĮxtern unsigned char twi_rx_index // data index in the receive bufferĮxtern unsigned char twi_result // holds the result of the last TWI transaction #define EEPROM_TWI_BUS_ADDRESS (0xA0 > 1) * 7 bit TWI bus slave address of the AT24C02B 2kbyte EEPROM */ Here is the code, i got it from cvAVR help: #include So I know the data successfully stored in eeprom. I'm trying to write and read to external eeprom (AT24c02B) then show the data bytes that store in eeprom to LED in PORTB and or to LCD.