This application note describes a reference system which illustrates how to build an embeddedPowerPC® system using the Xilinx 1-Gigabit Ethernet Media Access Controller processor core.This system has the PLB_Gemac configured to use Scatter/Gather Direct Memory Access andthe Serializer/Deserializer (SerDes) interface. This application note describes how to set up thespecific clocking structure required for the SerDes interface and the constraints to be added tothe UCF file. This reference system is complete with a standalone software application to testsome of the main features of this core, including access to registers, DMA capabilities, transmitand receive in loopback mode. This reference system is targeted for the ML300 evaluationboard.
隨著新研發(fā)單板上高速Serdes信號的增多，信號完整性測試顯的越來越重要，本文檔圍繞Serdes信號的眼圖抖動測試總結(jié)一些測試注意事項。新研發(fā)單板上高速Serdes信號速率高達2.45G，一些時鐘信號上升/下降沿達到400ps左右，必然需要測量Serdes信號的眼圖、抖動，在這里總結(jié)一些測試經(jīng)驗和注意事項。UBPG1單板上有如下幾種高速數(shù)據(jù)SERDES信號：1. GE SerDes接口(SGMII接口標(biāo)準(zhǔn))2. AIF SerDes接口(CPRI接口標(biāo)準(zhǔn))3. IQ SerDes接口(類CPRI接口標(biāo)準(zhǔn)，自定義幀格式)4. 光口 SerDes接口(CPRI接口標(biāo)準(zhǔn))對于SERDES信號，其信號電氣特性由IEEE協(xié)議規(guī)定，在協(xié)議中會給出相應(yīng)的眼圖測試模板及抖動指標(biāo)，部分芯片廠家會在DATASHEET中給出單獨的眼圖測試模板及抖動指標(biāo)（一般會比協(xié)議要求的更寬松）。UBPG1單板上的SerDes接口按電氣特性分有兩種，一種是SGMII接口（用1000-BASE-CX模板，IEEE協(xié)議39節(jié)）；一種是CPRI接口（用XAUI模板，IEEE協(xié)議49節(jié)）。
