Private Transaction

In Private Write Transfer, following the address header, the Controller will continue to send 9-bit I3C Data Words (8-bit Data and a Parity T-bit). The data becomes available for the user to read from the I3CxRXB Receive Buffer. The Controller can continue to send data until it reaches the maximum data write length specified in the I3CxMWL register, and then ends the transaction with a Stop or Restart. The Controller determines the maximum data write length by using the SETMWL CCC. The Controller can read back this data using the GETMWL CCC.

The Private Write Transaction Flow is shown in Figure 1. The general frame format for Private Write Transaction is shown in Figure 2 and a pseudo-code is shown in Pseudo-code for Private Write Transaction below.

Before sending any data, it is recommended to check the maximum data read length that the Controller will accept by reading the value in the I3CxMRL register. The Controller determines the maximum data read length, if possible, by using the SETMRL CCC. The Controller can read back this data using the GETMRL CCC.

The Private Read Transaction Flow is shown in Figure 3. The general frame format for Private Read Transaction is shown in Figure 4 and a pseudo-code is shown in Pseudo-code for Private Read Transaction below.

Figure 1. Private Write Transaction Flow

Figure 2. Private Write Transfer Frame Format

Copyuint8_t rxData[SIZE];

uint8_t I3C1_Target_PrivateWrite()
{
    uint16_t i = 0;

    // Check Target's operating mode first
    if(I3C1STATbits.OPMD != 0b01) {
        return 1;   // Target is operating in I2C mode, abort
    }

    // Check if Dynamic Address Match occured in Write mode
    if(!I2C1STATbits.DADRIF || !I3C1STATbits.RNW == 0b10) {
        return 1;   // abort if no dynamic address match or Read mode
    }

    while(i < SIZE) {
        // Wait for data to become available in Rx Buffer
        while(!I3C1STATbits.RXBF);

        // Read data from Receive buffer and increment pointer
        rxData[i++] = I3C1RXB;

        // Check if maxWrLen overflow
        if(I3C1ERRIR1bits.MWLOEIF) {
            // Controller has exceeded Max Write Length
            // Take appropriate action
        }

        // Perform error checking if desired
        // Check for Rx Overrun Error or Rx Read Error
        // if(I3C1ERRIR0bits.RXOIF || I3C1ERRIR1bits.RXREIF) { ... }

        // Check for Stop or Restart for End of Transaction
        if(I3C1PIR0bits.PCIF || I3C1PIR0bits.RSCIF || I3C1PIR1bits.TCOMPIF) {
            return 0;  // end of transaction with successful write
        }
    }

    // Code execution reaches here when rxData[] is full 
    // Wait for Stop or Restart for End of Transaction
    while(!I3C1PIR0bits.PCIF && !I3C1PIR0bits.RSCIF && !I3C1PIR1bits.TCOMPIF) {
        // While waiting, check for additional errors (optional)
        // if(I3C1ERRIR1bits.MWLOEIF || I3C1ERRIR0bits.RXOIF || I3C1ERRIR1bits.RXREIF) { ... }
    }

    return 1;   // end of transaction with possible data overflow
}

Figure 3. Private Read Transaction Flow

Figure 4. Private Read Transfer Frame Format

Copyuint8_t txData[SIZE];

uint8_t I3C1_Target_PrivateRead()
{
    uint16_t i = 0;

    // Check Target's operating mode first
    if(I3C1STATbits.OPMD != 0b01) {
        return 1;   // Target is operating in I2C mode, abort
    }

    // Check if Dynamic Address Match occured in Read mode
    if(!I2C1STATbits.DADRIF || !I3C1STATbits.RNW == 0b01) {
        return 1;   // abort if no dynamic address match or Write mode
    }

    while(i < SIZE) {
        // Wait for Tx Buffer to become empty
        while(!I3C1STATbits.TXBE);

        // Write data to Transmit buffer and increment pointer
        I3C1TXB = txData[i++];

        // Check if maxRdLen overflow
        if(i >= I3C1MRL) {
            // Software has exceeded Max Read Length set by the Controller
            // Take appropriate action
        }

        // Perform error checking if desired
        // Check for Tx Underrun Error or Tx Write Error
        // if(I3C1ERRIR0bits.TXUIF || I3C1ERRIR1bits.TXWEIF) { ... }

        // Check for Controller abort (possibly premature)
        if(I3C1PIR0bits.PCIF || I3C1PIR0bits.RSCIF || I3C1PIR1bits.TCOMPIF) {
            return 1;  // end of transaction with Controller abort
        }
    }

    // Code execution reaches here when all data from txData[] has been sent 
    // Wait for Stop or Restart for End of Transaction
    while(!I3C1PIR0bits.PCIF && !I3C1PIR0bits.RSCIF && !I3C1PIR1bits.TCOMPIF) {
        // While waiting, check for additional errors (optional)
        // if(I3C1ERRIR0bits.TXUIF || I3C1ERRIR1bits.TXWEIF) { ... }
    }

    return 0;   // end of transaction with possible data underflow
}