怎么为单片机和DAC放大器构建独立板的效果

SPI需要短的电线。最高的速度，最短的……我可以想象一些20-30cm @ 1MHz，和lt；10 @ 10MHz等。



      以下为原文

    SPI wants short wires. The highest the speed, the shortest...
I can imagine some 20-30cm @1MHz, <10 @10MHz etc...

它们会有多远？VCC是3.3伏吗？你会使用什么频率？



      以下为原文

    How far away will they be?
Will Vcc be 3.3volts?
What frequency will you be using?

我所说的距离将小于10cm（从每个板的头到头）。频率将是音频，但不确定它是什么。电压是3.3V。我想我可以先行一步。谢谢。



      以下为原文

    the distance i would say would be less than 10cm(from header to header of each board). the frequency would be for audio but not sure yet what it is. the voltage is 3.3V.
 
i guess i can go ahead with the prototype.
 
thank you
 
 

立体声高保真音响？CD质量（16位，44.1kHz，立体声），将需要至少2x16x4100＝1.411兆赫。



      以下为原文

   
stereo hi-fi audio?
CD quality (16 bit, 44.1kHz, stereo), would need at least 2x16x44100 = 1.411 MHz
 

HI，1）如果在2个SPI接口之间的距离小于10厘米而没有任何其他强的电干扰，那么最有可能在较低频率下获得可靠的通信，外部接口用于连接对等体。2）假设SPI为20MHz，需要32个时钟来写入。D最小同步高时间，然后SPI延迟是（500×32 + 35）NS＝16.35USEC。假设DAC输出稳定为0.5 USEC。因此，总更新时间为2.135USEC（DAC沉降+SPI延迟），为零到满刻度步骤。这是为了从一个精确的DAC产生方波输出。另外的过渡步骤将进一步降低更新时间。如果你的系统需求是2.135USEC更新时间为16位分辨率，这是468 kbps的转换，那么你需要在20 MHz的SPI。如果您的需求是46 kbps的转换（典型的音频应用），那么2 MHz SPI时钟应该是好的。希望它有用。谢谢，



      以下为原文

    Hi,
 
1)
If the distance is less than 10 cm between 2 spi interfaces without any other strong electrical interference, you would most probably get reliable communication at lower frequencies with external wires used for interfacing the peers.
 
2)
Lets assume SPI at 20MHz and you need 32 clocks to write and minimum SYNC high time, then
SPI delay is (500X32+35) ns = 16.35usec.
Assume the DAC output settling is 0.5 usec.
Therefore, the total update time is 2.135usec (DAC settling + SPI delay) for zero to full scale step.

This is for generating square wave output from a precision DAC.
Additional steps for transition will slow down the update time further.
 
If your system requirement is 2.135uSec update time for 16 bit resolution, which is  468 Kbps conversion, then you need SPI at 20 MHZ.

If your requirement is 46 Kbps conversion (typical audio applications), then 2 Mhz SPI clock should be good.

Hope it is useful.
 
Thanks,
 

任何答复都是有用的，非常感谢。是的，它是高质量的音频（音乐MP3等）。我想设置24位DAC。我使用DV3200 32板作为设计参考。我现在意识到，微控制器板和DAC/AMP子板实际上使用I2C和SPI进行通信。实际上，在示意图中，我认为I2C更常用。从微控制器上的SPI和I2C通信终止于DAC/AMP子板上的J1（20针）和J2（12针）头。而DAC只接收时钟的I2C信号（无SPI）。在这种情况下，我不理解SPI的目的。在我的情况下，我能用SPI替换I2C信号吗？SPI不是比I2C更好的音频样本传输吗？或者是在设计DV3200 32中使用I2C？



      以下为原文

    any replies is helpful, thank you very much.
 
yes it is for high quality audio(music mp3 etc). i wanted to setup 24bit DAC.
 
i am using the DV320032 board as design reference. i realized now that the microcontroller board and the DAC/amp daughter board is actually using I2C and SPI to communication. actually in the schematic it looks to me that the I2C is more often used.
 
the SPI and I2C communication from microcontroller terminate at the J1(20 pin) and J2(12 pin) headers on the DAC/amp daughter board. while the DAC is only receiving I2C signals for clocks(no SPI). I am not understanding the purpose of SPI in this case.
 
Can i replace I2C signals with the SPI in my case? isn't SPI better than I2C for transfer of audio samples? or is it that I2C is used for specific purpose in the design of DV320032?

我认为你混淆了I2C和I2S。I2S是一种用于音频数据传输的SPI超集。PIC使用SPI外设来做I2S。DAC子板使用一个（SPI/I2S）通道进行音频数据（J1上的PIN 10、12、13、14）。I2C是完全不同的协议，并且在DAC子板上没有使用。



      以下为原文

    I think you are confusing I2C and I2S. I2S is a (sort of) superset of SPI designed for audio data transfer. PIC's use the SPI peripherals to do I2S. The DAC daughterboard uses one (SPI/I2S) channel for audio data (pins 10,12,13,14 on J1).
 
I2C is a different protocol altogether, and is unused on the DAC daughterboard.

我有20厘米的电缆运行到SPI设备（NFR24L01+），我必须把一个大电容器（330uF）在3.3V VDD，否则它不能传输。（在一个面包板上）小帽子不起作用。在另一块板上，电缆是5CMS，我不需要帽子。



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    I have 20cm cable running to a spi device (nRF24L01+), I had to put a big capacitor (330uF)on the 3.3v vdd otherwise it could not transmit.  (On a breadboard)
 
Smaller caps did not work.
 
On another board the cable was 5cms and I didn't need the cap.
 

你好，我附了DV3200 32的框图，它显示了PIC32和子Boad之间的I2C链接。



      以下为原文

   


hi,
 
i attached the block diagram of DV320032 and it shows I2C links between PIC32 and daughter boards.
 
http://imgur.com/a/IhBJD
 
 
 
 
   Attached Image(s)

嗨，我认为他们刚刚带来了I2C1到20路报头（这样你就可以让你自己的女儿板和使用它）如果你看提供的子卡的示意图（项目21）不使用I2C，仅仅是USAT 1和包含I2S数据的GPIO引脚5，6，8，9。



      以下为原文

    Hi,
 
I think that they have just brought I2C1 up to the 20 way header (so that you can make your own daughter board and use it) If you look at the schematic of the daughter card supplied (item 21) I2C is not used, just USART 1 and the GPIO pins 5,6,8,9 which contain I2S data.

重试，附件不起作用…



      以下为原文

    retry,
attachment did not work...

@ SiMnG123，@ BMD是正确的，看起来这个系统使用的是I2S（我不知道）。所以我只需要实现下面的信号线，如下所示。



      以下为原文

    @simong123,@BMD are right, it looks like this system is using I2S(which i didn't know about).
 
So i only need to implement the following signal lines as ticked shown below?
 
 
   Attached Image(s)

嗨，是的，他们的DAC卡（提供工具包）只使用那些信号。



      以下为原文

    Hi,
 
Yes, their DAC card (supplied with the kit) only uses those signals.
 

嗨，如果SPI信号线比几厘米长，每个信号线中的串联电阻可能是合理的。在20欧姆和100欧姆之间的值可以工作，已经看到了许多图，使用27欧姆或33欧姆值。这一点是为了减少由于高阻抗端部的信号反射而产生的噪声。电线。迈西尔



      以下为原文

    Hi,
If SPI signal lines are longer than a few centimeters, a series resistor in each signal line may be sensible. 
Value between 20 Ohm and 100 Ohm may work, have seen many diagrams using 27 Ohm or 33 Ohm values.
The point is to reduce noise due to signal reflections from the high impedance end of the wire.
 
   Mysil