Crazypedia
12 lines
540 B
Markdown
12 lines
540 B
Markdown
# XL9555 I/O expander
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A driver for the `XL9555` 16-bit I2C-bus I/O expander, used by several LilyGO boards
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(e.g. T-Deck Pro Max) for power-rail enables, reset lines, and antenna/audio routing.
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Its register map is PCA9555-compatible: two 8-bit ports for input, output, polarity
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inversion, and direction, addressed as pins 0-15 (port 0 = pins 0-7, port 1 = pins 8-15).
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It does not support pull-up/down resistors or high-impedance outputs; requesting those
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flags returns `ERROR_NOT_SUPPORTED`.
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License: [Apache v2.0](LICENSE-Apache-2.0.md)
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