2 Host Read/Write Data

In this use case, the microcontroller is configured in I²C Host mode using the MSSP1 instance of the MSSP peripheral, and through multiple examples it communicates with different I²C client devices found on the PICkit Serial I²C Demo Board.

Code Examples:

• MCC Generated (Melody)
• Bare Metal Code

Both the MCC Generated and Bare Metal code examples implement the following steps:

• To transmit data as an I²C host, the following sequence must be implemented:

  1. Establish connection to I²C Device
     • Generate the Start condition by setting the SEN bit in the SSPxCON2 register.
     • The SSPxIF flag in the PIR3 register is set by hardware on completion of the Start condition and must be cleared by software.
     • Load the client address into the SSPxBUF register.
     • Clear SSPxIF flag in the PIR3 register indicating that the host is ready for another byte and must be cleared by software.
     • Check the ACKSTAT bit in the SSPxCON2 register.
  2. Write the desired register to client device
     • Load the register address in the SSPxBUF register.
     • The SSPxIF flag in the PIR3 register is set by hardware indicating that the client is ready for another byte and must be cleared by software.
     • Check the ACKSTAT bit in the SSPxCON2 register.
  3. Write a byte of data to the client device
     • Load the data in the SSPxBUF register.
     • The SSPxIF flag in the PIR3 register is set by hardware indicating that the client is ready for another byte and must be cleared by software.
     • Check the ACKSTAT bit in the SSPxCON2 register.
  4. End I²C connection
     • To end the transmission, generate the Stop condition by setting the PEN bit in the SSPxCON2 register.

  

• To receive data as an I²C host, the following sequence must be implemented:

  1. Establish connection to I²C Device
     • Generate the Start condition by setting the SEN bit in the SSPxCON2 register.
     • The SSPxIF flag in the PIR3 register is set by hardware on completion of the Start condition and must be cleared by software.
     • Load the client address into the SSPxBUF register.
     • Clear SSPxIF flag in the PIR3 register indicating that the host is ready for another byte and must be cleared by software.
     • Check the ACKSTAT bit in the SSPxCON2 register.
  2. Receive and ACK data byte (Repeat N-1 times)
     • Set the RCEN bit to enable the Receive mode.
     • Clear SSPxIF flag in the PIR3 register indicating that the host is ready for another byte and must be cleared by software.
     • Read data from the SSPxBUF register.
     • Send an Acknowledge bit to tell the device to send the next byte.
     • Clear SSPxIF flag in the PIR3 register indicating that the host is ready for another byte and must be cleared by software.
  3. Receive last byte in frame
     • Set the RCEN bit to enable the Receive mode.
     • The SSPxIF flag in the PIR3 register is set by hardware and must be cleared by software.
     • Read data from the SSPxBUF register.
     • Send a Not Acknowledge bit to stop receiving bytes.
     • Clear SSPxIF flag in the PIR3 register indicating that the host is ready for another byte and must be cleared by software.
     • To end the transmission, generate the Stop condition by setting the PEN bit in the SSPxCON2 register.