134 lines
2.4 KiB
Markdown
134 lines
2.4 KiB
Markdown
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# I²C Module
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| Since | Origin / Contributor | Maintainer | Source |
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| :----- | :-------------------- | :---------- | :------ |
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| 2014-12-22 | [Zeroday](https://github.com/funshine) | [Zeroday](https://github.com/funshine) | [i2c.c](../../../app/modules/i2c.c)|
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## i2c.address()
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Setup I²C address and read/write mode for the next transfer.
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#### Syntax
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`i2c.address(id, device_addr, direction)`
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#### Parameters
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- `id` always 0
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- `device_addr` device address
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- `direction` `i2c.TRANSMITTER` for writing mode , `i2c. RECEIVER` for reading mode
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#### Returns
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`true` if ack received, `false` if no ack received.
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#### See also
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[i2c.read()](#i2cread)
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## i2c.read()
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Read data for variable number of bytes.
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#### Syntax
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`i2c.read(id, len)`
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#### Parameters
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- `id` always 0
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- `len` number of data bytes
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#### Returns
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`string` of received data
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#### Example
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```lua
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id = 0
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sda = 1
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scl = 2
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-- initialize i2c, set pin1 as sda, set pin2 as scl
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i2c.setup(id, sda, scl, i2c.SLOW)
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-- user defined function: read from reg_addr content of dev_addr
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function read_reg(dev_addr, reg_addr)
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i2c.start(id)
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i2c.address(id, dev_addr, i2c.TRANSMITTER)
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i2c.write(id, reg_addr)
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i2c.stop(id)
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i2c.start(id)
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i2c.address(id, dev_addr, i2c.RECEIVER)
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c = i2c.read(id, 1)
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i2c.stop(id)
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return c
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end
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-- get content of register 0xAA of device 0x77
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reg = read_reg(0x77, 0xAA)
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print(string.byte(reg))
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```
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####See also
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[i2c.write()](#i2cwrite)
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## i2c.setup()
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Initialize the I²C module.
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#### Syntax
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`i2c.setup(id, pinSDA, pinSCL, speed)`
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####Parameters
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- `id` always 0
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- `pinSDA` 1~12, IO index
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- `pinSCL` 1~12, IO index
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- `speed` only `i2c.SLOW` supported
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#### Returns
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`speed` the selected speed
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####See also
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[i2c.read()](#i2cread)
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## i2c.start()
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Send an I²C start condition.
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#### Syntax
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`i2c.start(id)`
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#### Parameters
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`id` always 0
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#### Returns
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`nil`
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####See also
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[i2c.read()](#i2cread)
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## i2c.stop()
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Send an I²C stop condition.
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#### Syntax
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`i2c.stop(id)`
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####Parameters
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`id` always 0
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#### Returns
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`nil`
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####See also
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[i2c.read()](#i2cread)
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## i2c.write()
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Write data to I²C bus. Data items can be multiple numbers, strings or lua tables.
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####Syntax
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`i2c.write(id, data1[, data2[, ..., datan]])`
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####Parameters
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- `id` always 0
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- `data` data can be numbers, string or lua table.
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#### Returns
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`number` number of bytes written
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#### Example
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```lua
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i2c.write(0, "hello", "world")
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```
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#### See also
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[i2c.read()](#i2cread)
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