板卡上ARM型号TM4C129DNCPDT,通过MII和DP83620连接,DP83620连接安华高SFP的HFBR57E5.
硬件原理图如附件。
现在的问题是,上电后ARM不烧写程序,只连接SFP的发送光纤到MOXA光电转化器的话,MOXA显示可以link。
可是如果我把SFP的接收光纤也连到MOXA光电转化器的话,MOXA就显示不能link,现在还不能找到原因,希望TI能够帮助分析下电路。
我感觉PHY在Fiber模式下能不能link和软件没关系,只和硬件有关。
Andrew Du:
Hi, 如果是FIBER mode,DP83820还是需要配置的,上电默认是双绞线mode。
The DP83620 supports both Twister Pair (100BASE-TX and 10BASE-T) and Fiber (100BASE-FX) media.The port may be configured for Twisted Pair (TP) or Fiber (FX) operation by strap option or by registeraccess.At power-up/reset, the state of the RX_ER pin will select the media for the port. The default selection istwisted pair mode, while an external pull-down will select FX mode of operation. Strapping the port into FXmode also automatically sets the Far-End Fault Enable, bit 3 of PCSR (16h), the Scramble Bypass, bit 1of PCSR (16h) and the Descrambler Bypass, bit 0 of PCSR (16h). In addition, the media selection may becontrolled by writing to bit 6, FX_EN, of PCSR (16h).