usb转串口生成的端口 advanced 参数配置

[落花生雪]

usb转串口生成的端口 advanced 参数配置:在advanced 参数选项里面有一个 Latency Timer（msec）选项，不晓得这个参数具体代表什么意思？哪位兄弟知道还望告知一下，在此多谢了

[of123]

是转换器的缓存时间，可以尽量设置小一些。 见 http://www.chipkin.com/reducing-latency-on-com-ports/

[of123]

下面是 FTDI 的解释： The default settings of the device driver assume typical data transfers of hundred to thousands or more bytes at a given time. Some applications, such as a GPS device, only send data in short packets, often only a few bytes. If this is the case, it may be necessary to adjust the drivers buffer size and/or latency timer to smaller values. These values can be adjusted through the Advanced driver options as noted in Figure 2.13. The buffer size can be reduced to 64 bytes. The latency timer can be set as low as 2ms. A setting of 1ms will cause unnecessary USB traffic and could adversely affect data transmission. 大意是说，缺省设定是大量数据传输的，因此转换器内的缓存空间和等待时间都设得比较长。只有当缓存满或延迟时间到，转换器才会把数据上传到 USB 主机。如果你是小包传输，可以将缓存空间和延迟时间都缩小，省得传输完了还在干等。但太小了，会增加 USB 传输开销。

[落花生雪]

不好意思， 点错了，没给你分，实在抱歉啊。。。。。。。。。。