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Optimizing Baud Rate Settings for External Mode Communication

For External Mode to function correctly, it is essential that the following three baud rates are closely aligned, with a permissible variance of up to approximately 5%:

  • SCI-A Baud Rate: The baud rate configured for the Serial Communication Interface-A.

  • On-Board FTDI Chip Baud Rate: The baud rate that the FTDI chip, integrated on the target hardware.

  • Windows COM Port Baud Rate: The baud rate set for the corresponding COM port in Windows that facilitates communication with the target.

This alignment ensures seamless and error-free data transmission between your development environment and the target hardware.

Configure Baud Rates for Effective External Mode Communication

For example, when configuring the F28379D Launchpad for External Mode, it is crucial to ensure the compatibility of baud rates across three key components to guarantee smooth and error-free communication:

  • SCI-A Baud Rate: On the F28379D Launchpad, the Serial Communication Interface-A (SCI-A) can be configured for baud rates up to (12.5e6 bits/sec).

  • FTDI Chip Baud Rate: FT2232HQ is the FTDI serial chip on board and it supports up to 12 Mbaud in UART mode.

  • Windows COM port baud rates: The window OS provides support for baud rates like: 300, 600, 1200, 1800, 2400, 4800, 7200, 9600, 14400, 19200, 38400, 57600, 115200, 230400, 460800, 921600, etc in the same sequence.

Given these specifications, selecting a baud rate of either 5 million bits per second (5e6) or 12 million bits per second (12e6) will meet the criteria for all three components, ensuring that External Mode operates effectively on the F28379D Launchpad.

For other baud rates, even though it is a valid SCI rate, it might fail the other two criteria and External Mode won't run on the target.

Baud Rate Verification

To verify which Baud Rate combination works, the baud rate was increased in steps of 0.5 Mbps in the Serial Communication Using SCI Blocks example.

The received data was verified on the host side and the corresponding baud rate was validated.

See Also

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