如何同时使用多个DAC？

嗨，
使用Xilinx Blockset时的一个提示。
您应该将WaveScope用于数字信号，而不是示波器。
它提供了更紧凑的视图，可以处理总线以及不同的基数甚至模拟样式显示格式。
和...
什么是实际问题？
需要什么样的帮助？
并非所有网关都具有IOB LOC属性。
您可以在Sytem Generator Block中使用“Bitstream”代替“HDL Netlist”。
因此，您可以直接使用Impact来配置FPGA，而不是使用ISE首先从Netlist生成Bitfile。
有一个很好的模拟 
Eilert



以下为原文

Hi,
one hint when working with the Xilinx Blockset.
Instead of the scopes you should use WaveScope for digital signals.
It offers a more compact view and can handle busses as well with different radices and even analog style display format.
 
And...
what's the actual question?
What kind of help is needed?
 
Not all Gateways have IOB LOC atributes.
Instead of "HDL Netlist" you might use "Bitstream" in teh Sytem Generator Block.
Thus you can directly use Impact to configure the FPGA instead of using ISE to generate the Bitfile from the Netlist first.
 
Have a nice simulation
  Eilert

Thanx Eliert ....
我需要使用板载dac上可用的4个引脚A，B，C，D同时在cro上看到2个或更多正弦波....所以在我的模型中需要更改r .....目前即时使用地址
0000使用dac A获得所需的模拟输出......



以下为原文

Thanx Eliert....
 
i need to see 2 or more  sine wave simultaneously on cro using the 4 pins A, B , C, D available on the onboard dac ....so what changes r needed in my model.....presently i m using the address 0000 for using dac A to get the required analog output...

嗨，
最简单的解决方案是将DAC地址字段设置为“1111”，同时选择所有四个DAC。
但是你有四个相同的信号。
我怀疑那就是你要找的东西。
相反，您可以尝试这种方法：
你需要一个两位计数器和一个4：1多路复用器。
计数器将选择不同的MUX输入。
然后，您还应该有四个提供序列化样本数据的数据源。
您已经有一些关注SPI数据帧的电路。
将该电路中的数据设置为零。
将couter值放入地址字段。
使用一些组合逻辑在适当的时间将SPI数据帧与MUX输出相结合。
如果完成，您应该有四个独立的DAC输出信号，无论您使用数据源创建的波形如何。
请记住，对于恒定的SPI传输速率，DAC采样率将除以4。
有一个很好的综合 
Eilert



以下为原文

Hi,
the most simple solution nwould be to set the DAC address field to "1111", which selects all four DACs simultaneously.
But then you have four identical signals. I doubt that that's what you are looking for.
 
Instead you might try this approach:
You need some two bit counter and a 4:1 mux.
The counter will select the different MUX inputs.
Then you also should have four data sources that that provide the serialized sample data.
You already have some circuit that cares about the SPI data frames.
Set the datafiled in that circuit to zero.
Put the couter value into the address field.
Use some combinatorical logic to combine the SPI data frame with the MUX output at the right time.
 
If done right you should have four independent DAC output signals of whatever waveform you created with your data sources.
 
Keep in mind that for a constant SPI transmission rate your DAC sample rate will be divided by four.
 
Have a nice synthesis
     Eilert

thanx Eliert，
这非常有帮助。
我希望你将来能继续帮助我。



以下为原文

thanx Eliert, that was very helpful. i hope u will keep helping me in future.

我能够使用多路复用器获得四个输出，但是dac没有保留值......我想在cro上同时看到4个输出。
我该怎么办？



以下为原文

i am able to get four outputs using multiplexer but the dac is not retaining the values.....i want to see 4 outputs simultaneously on cro. what should i do?