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C28x-SCI_A, C28x-SCI_B, C28x-SCI_C, C28x_SCI_D

You can set the following parameters for serial communications interface (SCI):

Enable loopback

Enable the loopback function for self-test and diagnostics. When this function is enabled, a C28x DSP Tx pin is internally connected to its Rx pin, and the DSP can transmit data from its output port to its input port to check the integrity of the transmission.

Suspension mode

The type of suspension to be used while debugging your program with Code Composer Studio™. When your program encounters a breakpoint, the suspension mode determines whether to perform the program instruction. The available options are:

  • Hard_abort—Stops the program immediately.

  • Soft_abort—Stops when the current receive/transmit sequence is complete.

  • Free_run—Continues running regardless of the breakpoint.

Number of stop bits

Specify the number of stop bits transmitted.

Parity mode

The type of parity to be used. The available options are:

  • None—Disables parity.

  • Odd—Sets the parity bit to one if you have an odd number of ones in your bytes, such as 00110010.

  • Even—Sets the parity bit to one if you have an even number of ones in your bytes, such as 00110011.

Character length bits

Length in bits of each transmitted or received character. The default value is 8.

Desired baud rate in bits/sec

Specify the desired baud rate.

Baud rate prescaler (BRR = (SCIHBAUD << 8) | SCILBAUD))

The value using which SCI baud rate is scaled. This value is based on LSPCLK.

Closest achievable baud rate (LSPCLK/(BRR+1)/8) in bits/sec

The closest achievable baud rate calculated based on LSPCLK and BRR.

Communication mode

Raw data is unformatted and sent whenever the transmitting side is ready to send, regardless of whether the receiving side is ready or not. Without a wait state, deadlock conditions do not occur and data transmission is asynchronous. With this mode, the receiving side could miss data, but if the data is noncritical, using raw data mode can avoid blocking processes.

When you select protocol mode, handshaking between the host and the processor occurs. The transmitting side sends $SND to indicate it is ready to transmit. The receiving side sends back $RDY to indicate it is ready to receive. The transmitting side then sends data and, when the transmission is completed, it sends a checksum.

Advantages of using protocol mode are:

  • Avoids deadlock

  • Determines whether data is received without errors (checksum)

  • Determines whether data is received by the processor

  • Determines time consistency; each side waits for its turn to send or receive

Note

Deadlocks can occur if an SCI Transmit block tries to communicate with multiple SCI Receive blocks on different COM ports while both transmit and receive blocks are in blocking mode. Deadlocks cannot occur on the same COM port.

Blocking mode

If this option is enabled, the system waits until data is available to read (when data length is reached). If this option is disabled, the system checks FIFO periodically (in polling mode) for data to read. If data is present, the block reads and outputs the contents. If data is not present, the block outputs the last value and continues.

Data byte order

Select an option to match the endianness of the data being moved.

Pin assignment (Tx)

Assign the SCI transmit pin to be used with the SCI module.

Pin assignment (Rx)

Assign the SCI receive pin to be used with the SCI module.

Note

All SCI modules are not available for all TI C2000 processors.

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