LPCXpresso IDE中的主题 Waveform generator with LPC1756 & UDA1330

Waveform generator with LPC1756 & UDA1330

lpcware — Thu, 16 Jun 2016 02:41:39 GMT

Content originally posted in LPCWare by RA1981 on Thu Jun 30 03:32:06 MST 2011
Hi,

I want to realize a waveform generator. Maximum signal frequency is ~3kHz.
The waveforms should be user selectable (sine, square, sawtooth, etc. or self-defined by user) and the amplitude should be also variable.
The output signal will be feed in a audio input.

I wonder if it would be possible by using a LPC1756 (LPC1768 for prototyping) and a UDA1330 audio DAC connected via the I2S interface.
I 'd realize the waveforms as tables saved in the LPC flash memory. For the frequency variation I'd use a DDS approach where table entries are skipped on higher frequencies.
The amplitude (volume) variation could be done by dividing/multiplying the table value before it's being sent to the audio DAC.

So, the first question is if it's generally possible with a LPC1756/LPC1768 and the audio DAC or would the processor be overloaded? I cannot estimate it, that's why I ask.

Second question is already deeper into my approach: the UDA1330 datasheet (http://www.nxp.com/documents/data_sheet/UDA1330ATS.pdf) states on page 5 that the WS (word-select) edge must fall on the negative edge of the BCK (bit-clock) signal.
I couldn't find a diagram where the I2S signals are shown including the MCLK signal (which has to be connected to the BCK signal of UDA1330 I assume).
The user manual of LPC17xx is located here:
http://www.nxp.com/documents/user_manual/UM10360.pdf

So, if anyone has some experience with I2S I'd be glad if I can get some hints, tips and tricks :)

Regards,

Ralf

Re: Waveform generator with LPC1756 & UDA1330

lpcware — Thu, 16 Jun 2016 02:41:39 GMT

Content originally posted in LPCWare by NXP_Europe on Fri Jul 08 05:07:12 MST 2011
Hi Ralf,

The LPC1756 is certainly able to do this! Have a look at the following MBED (LPC1768) synth project: http://mbed.org/users/lbaddam3/notebook/music-synthesizer-with-ps2-keyboard-input/
NXP provides a LPC1700 codebundle including a simple I2S example: http://ics.nxp.com/support/documents/microcontrollers/zip/mcb1700.code.bundle.lpc17xx.keil.zip
There is also a I2S UDA1380 example available from Code Red: http://support.code-red-tech.com/CodeRedWiki/RDB1768cmsisExampleProjects?action=AttachFile&do=get&target=RDB1768cmsis2.zip

This should get you started!

Re: Waveform generator with LPC1756 & UDA1330

lpcware — Thu, 16 Jun 2016 02:41:40 GMT

Content originally posted in LPCWare by RA1981 on Fri Jul 08 05:23:09 MST 2011
Hi,

thanks a lot for the examples.

One question regarding the CodeRed examples: You're referring to the audiometer example, right?

Regards,

Ralf

Re: Waveform generator with LPC1756 & UDA1330

lpcware — Thu, 16 Jun 2016 02:41:41 GMT

Content originally posted in LPCWare by paavo91 on Tue Jan 20 06:38:09 MST 2015
Hi RA1981!

Have you finished your generator project?
Greetz