73 lines
1.8 KiB
Markdown
73 lines
1.8 KiB
Markdown
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# Sigma-delta Module
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| Since | Origin / Contributor | Maintainer | Source |
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| :----- | :-------------------- | :---------- | :------ |
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| 2017-01-13 | [Arnim Läuger](https://github.com/devsaurus) | [Arnim Läuger](https://github.com/devsaurus) | [sigma_delta.c](../../../app/modules/sigma_delta.c)|
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This module provides access to the [sigma-delta](https://en.wikipedia.org/wiki/Delta-sigma_modulation) component. It's a hardware signal generator that can be routed to any of the output GPIOs.
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The signal generation is controlled by the [`setprescale()`](#sigma_deltasetprescale) and [`setduty()`](#sigma_deltasetduty) functions.
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## sigma_delta.close()
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Reenables GPIO functionality at the related pin.
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#### Syntax
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`sigma_delta.close(channel)`
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#### Parameters
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- `channel` 0~7, sigma-delta channel index
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#### Returns
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`nil`
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## sigma_delta.setprescale()
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Sets the prescale value.
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#### Syntax
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`sigma_delta.setprescale(channel, value)
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#### Parameters
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- `channel` 0~7, sigma-delta channel index
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- `value` prescale 1 to 255
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#### Returns
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`nil`
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#### See also
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[`sigma_delta.setduty()`](#sigma_deltasetduty)
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## sigma_delta.setduty()
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Sets the duty value.
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#### Syntax
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`sigma_delta.setduty(channel, value)`
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#### Parameters
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- `channel` 0~7, sigma-delta channel index
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- `value` duty -128 to 127
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#### Returns
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`nil`
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#### See also
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[`sigma_delta.setprescale()`](#sigma_deltasetprescale)
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## sigma_delta.setup()
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Routes the sigma-delta channel to the specified pin. Target prescale and duty values should be applied prior to enabling the output with this command.
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#### Syntax
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`sigma_delta.setup(channel, pin)`
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#### Parameters
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- `channel` 0~7, sigma-delta channel index
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- `pin` 0~33, IO index
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#### Returns
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`nil`
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#### Example
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```lua
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sigma_delta.setprescale(0, 128)
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sigma_delta.setduty(0, 0)
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sigma_delta.setup(0, 4)
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```
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