BF703 A boot stream via UART at a speed of 115200

Hi, we made our first printed circuit board with BF703 and found out a boot stream can't be loaded via UART at speeds above 57600. At a speed of 115200 the device returns <DF 89 00 80> as a response on '@' instead of the expected <BF xx xx 00>. Is this some error in our board or a boot stream just can't be loaded at a speed of 115200? The speed is supported by a BF707 evaluation kit. A crystal oscillator - 24 MHz; dividers are standard. UART clock - 18 MHz (judging by returned dividers); signal edges of '@' are accurate (was checked by a oscilloscope).

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  • Yes, if the UART speed is not greater than 57600 the device responds correctly:

      9600 -> <BF 75 00 00> - multicard and motherboard
     19200 -> <BF 3A 00 00> - multicard and motherboard
     38400 -> <BF 1D 00 00> - multicard and motherboard
     57600 -> <BF 13 00 00> - multicard and motherboard
    115200 -> <DF 89 00 80> - multicard
    115200 -> <DF 22 20 F0> - motherboard

    where:

      multicard - VScom PCI200L multicard port

    motherboard - PC motherboard port

    The part number of BF703:

    ADSP-703

    BBCZ-4
    3237132.1-1.0
    #1531 CHINA

Reply
  • Yes, if the UART speed is not greater than 57600 the device responds correctly:

      9600 -> <BF 75 00 00> - multicard and motherboard
     19200 -> <BF 3A 00 00> - multicard and motherboard
     38400 -> <BF 1D 00 00> - multicard and motherboard
     57600 -> <BF 13 00 00> - multicard and motherboard
    115200 -> <DF 89 00 80> - multicard
    115200 -> <DF 22 20 F0> - motherboard

    where:

      multicard - VScom PCI200L multicard port

    motherboard - PC motherboard port

    The part number of BF703:

    ADSP-703

    BBCZ-4
    3237132.1-1.0
    #1531 CHINA

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