SPI core

Baud rate #3

Open ManuelStahl opened this issue over 14 years ago

Can someone explain how the numbers are related to the comments here:

    4'b0000: clkcnt <= #1 12'h0;   // 2   -- original M68HC11 coding
    4'b0001: clkcnt <= #1 12'h1;   // 4   -- original M68HC11 coding
    4'b0010: clkcnt <= #1 12'h3;   // 16  -- original M68HC11 coding
    4'b0011: clkcnt <= #1 12'hf;   // 32  -- original M68HC11 coding
    4'b0100: clkcnt <= #1 12'h1f;  // 8
    4'b0101: clkcnt <= #1 12'h7;   // 64
    4'b0110: clkcnt <= #1 12'h3f;  // 128
    4'b0111: clkcnt <= #1 12'h7f;  // 256
    4'b1000: clkcnt <= #1 12'hff;  // 512
    4'b1001: clkcnt <= #1 12'h1ff; // 1024
    4'b1010: clkcnt <= #1 12'h3ff; // 2048
    4'b1011: clkcnt <= #1 12'h7ff; // 4096

The idea was to follow the original HC11 encoding, but extending the range. Then people complained it wasn't straightforward ...

So now there is a linear implementation, with comments for the HC11 compatible encoding. Somewhat a mix-up.

Set it to your own preference ...

Richard

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