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从串行端口上的命令读取响应

hardware usb serial-port php

Andrey Tsarev · 技术社区 · 7 年前

我正在编写一个PHP应用程序,它使用串行设备来处理GSM调制解调器。因此,您可以通过 screen 当您编写命令时,您会得到一个响应。

我使用PHP与串行端口通信,并使用 sleep 要在命令之间等待,请使用 fopen 具有 w+ 标志和 fwrite 发送命令。我试着用 fread 函数来检查响应是否存在,但它不存在。如何在PHP中做到这一点?

1 回复 | 直到 7 年前

ralf htp 7 年前

概念上 f_read 如果端口配置正确,则应正常工作。有一个图书馆 php-serial 在…上 https://github.com/Xowap/PHP-Serial

这是 readPort() 功能:

public function readPort($count = 0)
    {
        if ($this->_dState !== SERIAL_DEVICE_OPENED) {
            trigger_error("Device must be opened to read it", E_USER_WARNING);
            return false;
        }
        if ($this->_os === "linux" || $this->_os === "osx") {
            // Behavior in OSX isn't to wait for new data to recover, but just
            // grabs what's there!
            // Doesn't always work perfectly for me in OSX
            $content = ""; $i = 0;
            if ($count !== 0) {
                do {
                    if ($i > $count) {
                        $content .= fread($this->_dHandle, ($count - $i));
                    } else {
                        $content .= fread($this->_dHandle, 128);
                    }
                } while (($i += 128) === strlen($content));
            } else {
                do {
                    $content .= fread($this->_dHandle, 128);
                } while (($i += 128) === strlen($content));
            }
            return $content;
        } elseif ($this->_os === "windows") {
            // Windows port reading procedures still buggy
            $content = ""; $i = 0;
            if ($count !== 0) {
                do {
                    if ($i > $count) {
                        $content .= fread($this->_dHandle, ($count - $i));
                    } else {
                        $content .= fread($this->_dHandle, 128);
                    }
                } while (($i += 128) === strlen($content));
            } else {
                do {
                    $content .= fread($this->_dHandle, 128);
                } while (($i 

+= 128) === strlen($content));
        }
        return $content;
    }
    return false;
}

( How to Read RS232 Serial Port in PHP like this QBasic Program )