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I2C ref doc 'repeated' description (#1589)

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* I2C ref doc 'repeated' description

* Note the non-endianness for one byte formats

* trigger rebuild
This commit is contained in:
Galen Nickel
2018-11-15 21:57:39 -08:00
committed by Peli de Halleux
parent ac9f9d1553
commit a6e4f63dea
5 changed files with 73 additions and 10 deletions
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32
docs/reference/pins/i2c-read-number.md
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@@ -1,4 +1,4 @@
# I2C Read Number
# i2c Read Number
Read one number from an I2C address using a specified number format.
@@ -7,6 +7,7 @@ pins.i2cReadNumber(0, NumberFormat.Int8LE, false);
```
### ~hint
**Simulator**
This function needs real hardware to work with. It's not supported in the simulator.
@@ -17,14 +18,21 @@ This function needs real hardware to work with. It's not supported in the simula
* **address**: the 7-bit I2C address of the device you want to read a number from.
* **format**: the [NumberFormat](/types/buffer/number-format) of the number value to read.
* **repeated**: repeated start, true - don't send stop at end.
* **repeated**: if `true`, a [repeated start condition](http://www.i2c-bus.org/repeated-start-condition/) is set to help make sure the number is read from the device with out an interruption. If set to `false` (the default), the number is read without setting a start condition more than once.
* **repeated**: if `true`, don't send a stop condition after the read. Otherwise, a stop condition is sent when `false` (the default).
### ~ hint
A [repeated start condition](http://www.i2c-bus.org/repeated-start-condition/) is set to help make sure that when you want to read multiple numbers from the device at one time, it can happen without interruption. A start conditon is sent (if **repeated** is `true`) each time a number is read without a matching stop condition. When the last number is read, the stop conditon can be sent by setting **repeated** to `false`. For single reads, don't use **repeated** or set it to `false`.
### ~
## Returns
* a number from the device with the [NumberFormat](/types/buffer/number-format) you asked for.
## Example
## Examples
### Read a big endian number from a device
The following example reads a number in big-endian, 16-bit, unsigned integer
format from the 7-bit I2C address `32`.
@@ -32,9 +40,23 @@ format from the 7-bit I2C address `32`.
Read a number from the device at a 7-bit I2C address as a 16-bit number. The `16`, big-endian, and integer chosen for the format.
```blocks
pins.i2cReadNumber(32, NumberFormat.UInt16BE, false);
let inValue = pins.i2cReadNumber(32, NumberFormat.UInt16BE, false);
```
### Repeated reads
Read three bytes from a device at address `33` at one time.
```blocks
let nums: number[] = []
nums[0] = pins.i2cReadNumber(33, NumberFormat.UInt8LE, true)
nums[1] = pins.i2cReadNumber(33, NumberFormat.UInt8LE, true)
nums[2] = pins.i2cReadNumber(33, NumberFormat.UInt8LE, false)
```
## See also
[i2c write number](/reference/pins/i2c-write-number)
[What's I2C?](http://www.i2c-bus.org/), [number format](/types/buffer/number-format)