mirror of https://github.com/openXC7/prjxray.git
30 lines
817 B
Markdown
30 lines
817 B
Markdown
RAMB36 features
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===============
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This fuzzer emits features that only are used in the RAMB36E1 cell. There are
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3 categories:
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- ECC
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- RAM extension
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- Odd address modes
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Odd address modes
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-----------------
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Most RAMB36E1 address widths are expressed by configuring the underlying
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RAMB18E1 to handle half of the data. So `RAMB36.READ_WIDTH = 4` is
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expressed as `RAM18_Y0.READ_WIDTH = 2` and `RAM18_Y1.READ_WIDTH = 2`. However
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two address widths (1 and 9) are odd (e.g. not divisible by 2). In these
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cases, a RAMB36E1 specific feature is used. So `RAMB36.READ_WIDTH = 9` is
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expressed as:
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- `RAMB18_Y0.READ_WIDTH_4`
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- `RAMB18_Y1.READ_WIDTH_4`
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- `RAMB36.BRAM36_READ_WIDTH_1`
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and `RAMB36.READ_WIDTH = 1` is expressed as:
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- `RAMB18_Y0.READ_WIDTH_1`
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- `RAMB18_Y1.READ_WIDTH_1`
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- `RAMB36.BRAM36_READ_WIDTH_1`
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