49 lines
1.6 KiB
Markdown
49 lines
1.6 KiB
Markdown
# spi Write
|
|
|
|
Write a data value to the SPI slave device and return its response.
|
|
|
|
```sig
|
|
pins.spiWrite(0);
|
|
```
|
|
|
|
Data values are written to a SPI slave device connected to the @boardname@ by the [SPI pins](/reference/pins/spi-pins). The data value might be either a command for the connected device or some value for its use. If the write operation causes the connected device to send a value back to the @boardname@, this will be the return value for the **spiWrite** function.
|
|
|
|
### ~ hint
|
|
|
|
**Simulator**: This function needs real hardware to work with. It's not supported in the simulator.
|
|
|
|
### ~
|
|
|
|
## Parameters
|
|
|
|
* ``value``: a [number](/types/number) which is the data value to send to the SPI slave device.
|
|
|
|
## Returns
|
|
|
|
* a [number](/types/number) value which is the response from the SPI slave device.
|
|
|
|
## Example
|
|
|
|
Send the command to read the value of the _WHOAMI_ register from the device connected to the SPI bus. The chip select line is connected to pin **0** and the SPI signals use pins **P13**, **P14**, and **P15**.
|
|
|
|
```blocks
|
|
pins.digitalWritePin(DigitalPin.P0, 1);
|
|
pins.spiPins(DigitalPin.P15, DigitalPin.P14, DigitalPin.P13);
|
|
pins.spiFormat(8, 3);
|
|
pins.spiFrequency(1000000);
|
|
pins.digitalWritePin(DigitalPin.P0, 0);
|
|
let command = pins.spiWrite(143);
|
|
let whoami = pins.spiWrite(0);
|
|
pins.digitalWritePin(DigitalPin.P0, 1);
|
|
basic.showNumber(whoami);
|
|
serial.writeLine("WHOAMI register value: " + whoami)
|
|
```
|
|
|
|
## See also
|
|
|
|
[spi pins](/reference/pins/spi-pins),
|
|
[spi frequency](/reference/pins/spi-frequency),
|
|
[spi format](/reference/pins/spi-format)
|
|
|
|
[SPI Programming](https://developer.mbed.org/handbook/SPI)
|