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Old 19th August 2012, 12:35 AM   #341
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Quote:
Originally Posted by twest820 View Post
I've had some time to work on my 4300 based DSP+DAC project lately, an offshoot of which is the attached spreadsheet for tracking pin assignments. NXP's cancelled packages and defined new pinouts since I started working on this but it should be correct barring typos or changes on NXP's part that I missed---it's based on the early June datasheet and manual. Anyone who happens to find errors, PM me the changes.
A smart move is to reorient your DSP+DAC project into a DSP + WM8580 (or WM8581) plus some salt and pepper enabling the same (credit card sized) board to sit into three different applications :
- general purpose stereo digital XO (with SPDIF in)
- DSS preamp (with SPDIF in)
- DSS speaker XO (mono XO - thus up to 8 channels per speaker - excellent for line arrays)

About DSS, read this : AES E-Library Philips DSS 930: A New Concept in Active Loudspeaker

With DSS, Philips used a trick to convey side-information on top of SPDIF, like the volume control info. They added a low frequency modulation on top of the SPDIF stream. We may replicate this. The scheme is documented in the Philips DSS930 and DSS940 Service Manuals. If you don't like this, you may add, as an option, a second Cinch for conveying the side info separately, kind of audiophile option.

A typical stereo DSS configuration needs one DSP in the preamp, and one DSP in each speaker. Thus, three credit card sized DSP boards in total.

Microchip PIC32MX2 28pin can deliver two I2S (bidirectional), plus one I2C. Microchip PIC32 tools are reliable, and inexpensive. This would be the inexpensive, uncomplicated starting point. WM8580 slightly underexpoited, not a big issue.

Wanting more bells and whistles like more GPIOs for driving LEDs and other peripherals? An infrared remote control? An external volume controller? Use a 44pin PIC32MX2. Consider this as the big brother of http://electrodesigns.net/blog/diyau...age/#more-1821

Infineon XMC4500 can deliver five (unidirectional I guess) I2S, plus one I2C. Slightly more expensive. More MIPS also. This time we get the WM8580 or WM8581 fully exploited.

Interoperability would exist between boards equipped with the 28pin PIC32MX2, the 44pin PIC32MX2, and the Infineon XMC4500.

After having done this, some demand will show for DSS boards only equipped with the DSP, designed for external DACs. Don't be fooled by this now. Only deal with such demand later on.

In a nutshell : keep it simple and stupid.

Manage to get your boards distributed by Sparkfun, Watterott and Elektor. With press coverage from Elektor and Hobby-Hifi.
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Old 21st August 2012, 10:52 PM   #342
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We discussed most of that a few pages back. I guess the one remark I have is if the analog portion of the playback channel has a good gain structure there's enough utilized bit depth in the DAC sending divided down samples over SPDIF for volume control isn't a big deal. Particularly if you've a source like a Squeezebox that automatically pads 16 bit data to 24 bit.

I'll spin up a separate thread once my build's farther along. The 43x0 parts have the IOs to make a basic board that's quite extensible---without really trying I ended up with schematic that supports up to 14 I2S links and at least five clock domains. I only need four links and one clock so that's all I'll write code for. But the extra routing is so trivial it'd be rather silly not to put the hardware capacity there in case need arises to write software to do something with it.
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Old 22nd August 2012, 08:22 PM   #343
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Originally Posted by steph_tsf View Post
This is exactly what we have waited for so long. Will you help us getting this running on NGX LPC4330 Xplorer? Using KEIL MDK ARM with ULINK2/ME or using LPC-Xpresso with NXP LPC-Link?
Sorry for late reply.
I am using Keil & J-link with my custom made development board based on LPC4330FBD144 chip.
Examples from NXP are available here: LPCware.com GIT server :: lpc43xx.git/tree
Now I am developing UAC2 firmware for full multichannel output testing...
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Old 22nd August 2012, 08:49 PM   #344
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Originally Posted by twest820 View Post
Cool. I've had some time to work on my 4300 based DSP+DAC project lately, an offshoot of which is the attached spreadsheet for tracking pin assignments.
There is very helpful tool for quick pin routing:
LPC43xx Pin Mux tool | www.LPCware.com

Last edited by a5856; 22nd August 2012 at 09:07 PM.
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Old 22nd August 2012, 10:39 PM   #345
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Thanks for the links! I'm looking forward to going through the samples. The pin mux tool is interesting as it doesn't support all pin assignments listed in the datasheet. I'll have to compile the differences and email the author.
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Old 22nd August 2012, 11:49 PM   #346
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Hmm, is it possible to buy a ULINK-ME on its own or is it always bundled with an eval board? I checked all the US distributors and they're always bundled, though $210ish for for an eval board + ULINK-ME isn't hugely far from $170 for a Red Probe with the 10 pin Cortex debug adapter. Main difference is MDK-Lite's 32k limit and steep licensing fees versus LPCXpresso's 128k limit and considerably less agressive pricing. But I'd be surprised to hit 32k and $40ish can quickly pay itself back in hassles avoided. ($300-400 for a ULINK2 is more than I'd prefer to spend.)

For folks who've used both environments all the way though to debugging, what's your preference? (I've only toyed with LPCXpresso so far.)

Last edited by twest820; 22nd August 2012 at 11:55 PM.
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Old 23rd August 2012, 06:51 AM   #347
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Originally Posted by twest820 View Post
($300-400 for a ULINK2 is more than I'd prefer to spend.)
There are more cheap variants.
For example: J-Link V8 ARM USB-JTAG Adapter Emulator - Black - Worldwide Free Shipping - DX
or Keil Ulink 2 ARM Multi-Function Emulator for SCM - White - Worldwide Free Shipping - DX

Last edited by a5856; 23rd August 2012 at 07:00 AM.
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Old 24th August 2012, 12:11 AM   #348
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Nice! I would guess it's probably just a change in the silkscreen on the box to say Real View instead of Keil. The Real View Ulink 2s eBay for as little as $0.01.
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Old 24th August 2012, 08:42 AM   #349
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Those last weeks the LPC4330 support improved thanks to:
- NGX LPC4330-Xplorer board ($56.42 - I already own two of them)
- LPCware
- lpc43xx.git (especially the lpc43xx SGPIO I2S for UDA1380)
- nxpUSBlib (grabbing audio from USB)
- LPC43xx Pin Mux Tool
Within a series of Open Source projects, let's develop a few "capes" or "shields" for the NGX LPC4330-Xplorer, and some demo softwares.
Do we get access to the two ARM cores?
Attached Images
File Type: jpg NGX LPC4330-Xplorer.jpg (146.6 KB, 135 views)
File Type: jpg Keil µVision 4 IDE.jpg (77.3 KB, 127 views)
File Type: jpg LPCXpresso IDE.jpg (169.0 KB, 125 views)
File Type: jpg Board connections and configurations.jpg (266.1 KB, 123 views)
File Type: jpg nxpUSBlib.jpg (123.8 KB, 120 views)
File Type: jpg lpc43xx.git.jpg (86.9 KB, 20 views)
File Type: jpg lpc43xx SGPIO I2S for UDA1380.jpg (162.4 KB, 22 views)
File Type: jpg LPC43xx Pin Mux Tool.jpg (107.7 KB, 21 views)
File Type: jpg Keil Ulink 2 ARM Multi-Function Emulator for SCM - White.jpg (61.2 KB, 25 views)
File Type: jpg J-Link V8 ARM USB-JTAG Adapter Emulator - Black.jpg (60.2 KB, 22 views)
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Old 24th August 2012, 01:26 PM   #350
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You can use either:
- a Red Probe+ (or original Red Probe)
- or the LPC-Link probe from an LPCXpresso board
to debug your LPC4350.

LPC_4350_Support
Attached Images
File Type: jpg Red Probe+ or LPC-Link probe.jpg (155.2 KB, 19 views)
File Type: jpg Red Probe +.jpg (39.0 KB, 18 views)
File Type: jpg LPC1227 LPCXPRESSO LPC-LINK.jpg (103.8 KB, 31 views)
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