spi_write_read()

向SPI传送数据读取接收数据

Description

int spi_write_read(int $spi_id, string $wbuf, string &$rbuf, int $rlen)

Parameters

$spi_id: SPI账号
$wbuf: 保存传送数据的变量 (string)
$rbuf: 读取数据保存的变量
$rlen: 读取数据长度

Return Value

读取或写的数据长度(byte)

Example

<?php
include "/lib/sd_340.php";
$rbuf = "";
$wbuf = "\x1E\x07";
$rlen = 0;
spi_setup(0);                                // configuring SPI
$rlen = spi_write_read(0, $wbuf, $rbuf, 2);  // writing and reading to/from the SPI
if($rlen == 2)
  echo "$rbuf\r\n";                          // outputting the received data
?>

See also