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杨涛

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[问答]

怎么在Displayport上实现HDMI

嗨,大家好,
我有一个带迷你Displayport接口的Kintex-7主板。
本周末,我尝试用HDMI运行HDMI
外部迷你Displayport转HDMI适配器。
但不幸的是我没有成功。
我将输出配置为IOSTANDARD = TMDS_33并使用了OBUFDS。
仅仅为了测试,我试图输出一个25 Mhz的时钟。
当我测量时,我只测量了零伏特。
我知道信号是差分的,但无论如何我应该看到一些东西
发生在线上。
由于Displayport电容器是串联的,因此需要外部适配器来摆脱AC耦合。
所以现在我的问题是,当我将差分输出配置为TMDS_33时,我通常在接收器的一侧
电阻为3.3V。
在电容器之前我还需要这样的电阻吗?
我可以使用内部上拉而不必更换硬件吗?
谢谢。

以上来自于谷歌翻译


以下为原文

Hi everyone,

I have a Kintex-7 board with a mini Displayport interface. This weekend I tried to get HDMI running with an
external mini Displayport to HDMI adapter. But unfortunately I wasn't successful.

I configured the outputs as IOSTANDARD = TMDS_33 and used an OBUFDS.
Just for testing, I tried to ouput a clock with 25 Mhz.
When I measured, I only measured zero volt. I know that the signal is differential but anyway I should see something
happen on the line.
Due to Displayport a capacitor is in series and therefore the external adapter is needed to get rid of the AC coupling.

So my question is now, when I configure the differential ouput as TMDS_33 normally I have at the side of the reciever
resistors to 3.3V. Do I need such resistors before the capacitor also?
Could I use internal pullups to don't have to change the hardware?

Thanks.

回帖(1)

张林锋

2019-3-19 09:35:25
我只是想扩展我的问题。所以有人都知道,DP ++如何处理发送HDMI信号。我的意思是你可以读取DP ++切换其I / O标准到输出HDMI的任何地方,并且需要无源适配器电压调整。就我而言
知道这个适配器并不是真正的被动而是他们的意思,它是由displayport提供的。为什么这样的芯片会存在这样的问题://datasheets.maximintegrated.com/en/ds/MAX9406.pdf对于双DVI这是另一种情况..
我的另一个问题是,当使用CML(TMDS_33)作为输出时,将100nF串联并在另一端添加带集成终端的CML接收器。
在C电阻到VCC之前我需要吗?
当用示波器测量时,我应该看到电容器上有一些电压摆动或?据我所知,只有在使用部分重新配置时才能在运行期间切换io标准。
那么是否可以在运行时将显示端口信号和开关驱动到显示端口而不进行部分重新配置?我会使用哪种I / O标准?

以上来自于谷歌翻译


以下为原文

I just want to expand my question.
So does anyone know, how DP++ handles sending HDMI signals.
I mean you can read anywhere that DP++ switches its I/O standard to output HDMI and a passive adapter voltage adjustment is needed.
As far as I know this adapter is not really passive instead they mean, it is powered by the displayport.
Why else would such a chip exist
http://datasheets.maximintegrated.com/en/ds/MAX9406.pdf
For dual-DVI this is another case ...

So another question of mine is, when using CML (TMDS_33) as output, putting 100nF in series and adding a CML receiver with integrated termination at the other end. Do I need before the C resistors to VCC? When measuring with an oscilloscope, I should see some voltage swing at the capacitor or?

As far as I know, the io standard could only be switched during runtime when partial reconfiguration is used. So is it possible to drive a displayport with either displayport signals and switch during runtime to HDMI without partial reconfiguring?
Which I/O standard I would use?
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