使用serdes芯片TLK1221连接一个1394设备

zhi wang2

Other Parts Discussed in Thread: TLK1221, TLK1211

我使用TLK1221连接一个1394设备，在初始化阶段需要进行速度协商，需要接收来自TI1394芯片的TONE信号，我使用TLK1221的LOOPEN发送tone，使用LOS来检测TONE，但是当我把LOOPEN拉高时，我为什么检测不到RXP和RXN上的LOS信号，只能检测到TXP和TXN上发出的信号，难道是内部自环了吗，但是根据数据手册上的图，LOS的检测只是检测接收端，跟内环没有关系啊。

11 年多前

0 Luke Sun 11 年多前

TI__Intellectual 1130 points

Hi zhi wang,

请去接口/时钟板块寻求那边专家的帮助，谢谢~

http://www.deyisupport.com/question_answer/analog/interface_and_clocks/f/59.aspx

0 Nick Dai 11 年多前

TI__Intellectual 2880 points

Hi Zhi,

如器件手册所述，LOOPEN使能的是内部环回，发送侧的数据在内部传输给接收侧的输入端。

When LOOPEN is high (active), the internal loopback path is activated. The transmitted serial data is directly routed to the inputs of the receiver. This provides a self-test capability in conjunction with the protocol device. The TXP and TXN outputs are held in a high-impedance state during the loopback test. LOOPEN is held low during standard operational state with external serial outputs and inputs active.