40 lines
1.1 KiB
Markdown
40 lines
1.1 KiB
Markdown
|
# read Buffer
|
||
|
|
|
||
|
|
Read available serial data into a buffer.
|
||
|
|
|
||
|
|
```sig
|
||
|
|
serial.readBuffer(64);
|
||
|
|
```
|
||
|
|
|
||
|
|
## Parameters
|
||
|
|
|
||
|
|
* **length**: the [number](/types/number) of characters of serial data to read.
|
||
|
|
|
||
|
|
## Returns
|
||
|
|
|
||
|
|
* a [buffer](/types/buffer) containing input from the serial port. The length of the buffer may be smaller than the requested length.
|
||
|
|
|
||
|
|
## ~hint
|
||
|
|
**Pause for more data**
|
||
|
|
|
||
|
|
If the desired number of characters are available, **readBuffer** returns a buffer with the expected size. If not, the calling fiber (the part of your program calling the **readBuffer** function) sleeps until the desired number of characters are finally read into the buffer.
|
||
|
|
|
||
|
|
The need to pause for more data is set by the @boardname@ **[serial mode](https://lancaster-university.github.io/microbit-docs/ubit/serial/#serial-modes)**.
|
||
|
|
## ~
|
||
|
|
|
||
|
|
## Example
|
||
|
|
|
||
|
|
Read character data from the serial port one row at a time. Write the rows to an LED display connected to the I2C pins.
|
||
|
|
|
||
|
|
```typescript
|
||
|
|
let rowData: Buffer = null;
|
||
|
|
for (let i = 0; i < 24; i++) {
|
||
|
|
rowData = serial.readBuffer(80);
|
||
|
|
pins.i2cWriteBuffer(65, rowData, false);
|
||
|
|
}
|
||
|
|
```
|
||
|
|
|
||
|
|
## See Also
|
||
|
|
|
||
|
|
[write buffer](/reference/serial/write-buffer)
|