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It may be a sloppy usage, or just unfamiliar to people used to dealing with the delights of 'codec packs' and getting oddball media to play back; but the term 'audio codec' appears to be what they use for the chip that handles talking to one or more mics and audio ins and outs and(possibly in addition to providing hardware accellerated processing of certain features) wraps that all up into a(fairly high speed; but conveniently low pin count and digital, I2S or similar inter-chip audio bus) for connection to the SoC.

At least in the case of the Pixel XL; the part in question is a Qualcomm WCD9335. The usual joys of actually finding Qualcomm datasheets apply; but it's referred to as a "WCD9335 audio codec" in a variety of places it is mentioned.

Given contemporary CPU power, I'm not sure if having the coding and decoding offboard is of much interest anymore; but using the offboard codec allows you to get away with supporting a wide variety of different audio capabilities(anywhere from just single mic and speaker to fancy array mics and zillions of audio ins and outs) with the same SoC implementing a relatively simple digital bus(no need to add a whole bunch of ADCs and DACs to every SoC just in case some high-end phone models want to use them); and allowing the designer to choose a codec chip based on how many mics and audio outs they need to support; whether they care about 'audiophile' DACs, etc.

Somewhat analogous to 'Intel HD Audio' on the PC side: this specifies a fairly cheap and flexible interface with some amount of standardization of how you talk to various features; but doesn't require adding ADCs and DACs to the CPU or chipset; and allows motherboard vendors to use any support chip that speaks HDA depending on their desired budget, number of audio ins and outs, interest in audio quality, etc.

They aren't the vendor used by the Pixel, to my knowledge; but take a look at Cirrus Logic's "'Codecs' page for a whole bunch of datasheets outlining the purpose and capabilities of chips referred to as 'audio codecs'.

A quick search with my local Australian electronics parts distributor shows up a nice $4.50 CS42L52 (in single quantities)
AC97, 8 input channels, 4 output channels, 24bit, 96k samples/sec. Oooh and it is even low power!

http://www.cirrus.com/en/produ...

Show me one thing your favourite $20/channel DAC does better that can be perceived by the human ear.

I also spent 4 years studying an EE degree, and although it was not especially focused on signal processing, I now work for a large pro audio company.

Some of the issues pointed to in this and other posts regarding oversampling and AA filters are not really relevant to the subject at hand, given the technology currently in use. A statement like 'oversampling at 192 kHz' shows a lack of knowledge regarding the kinds of audio converters that have been in use for a good while now. A Delta Sigma ADC running with an Fs of 48 kHz might often be oversampling at 3.072 MHz or 6.144 MHz. Anti aliasing filters that many people have mentioned are implemented digitally inside the converter (no need for external analog filters, which may well exhibit many of the problems mentioned), and actually have extremely good pass band ripple.

Look at datasheets for converters from manufacturers such as TI (burr brown), cirrus [page 36 here has detailed plots of 48, 96, and 192 kHz pass pand characterisitcs for the device, highlighting the fact that increasing the sampling rate does not improve pass band ripple for this device (also note the scale is 0.02 dB/div)], AKM, Wolfson micro You will find pass band pass responses that are flat to within less than +/- 0.05 dB over the audible range, and stop band attenuation in excess of 100 dB, whether sampling at 48 kHz or 192 kHz. If you can find anything in actual converter datasheets that points to better converter performance from selecting a higher sampling rate, I would be interested to see it.

All in all, the basics of sampling theory don't really help people to understant the real world issues in designing a moden high end audio device. And in the end, surely the proof of the pudding is in the blind tests, that never seem to show that anybody can tell any difference when moving to higher rates? Even if there were a few people who could hear this difference in some perfect listening envirmonment, would it really make sense for everyone else to go out and buy 192 kHz equipment?

Um. AFAIK in the specific case of c64 ethernet cards, they tend to use CS8900a chips (intended to run on an ISA bus, which is easily enough bridged to the C64) . Yes, some ethernet frame processing happens on chip, but the entire TCP/IP stack runs on the c64 (though a lot of enthusiasts have 20MHz SuperCPUs for their c64s...)

http://www.dunkels.com/adam/tfe/hardware.html
http://www.cirrus.com/en/products/pro/detail/P46.html

Datasheet, which you have obviously never read. Please see page 55.

Take a look at the posts on their forum. These guys are totally clueless.

http://arm.cirrus.com/forum/viewtopic.php?t=183

There's a fundamental misunderstanding here - GOOD Hardware engineers start out by asking "What OS vendor are you going to use?" before buying an eval board and dictating what OS to use by their choice of processor vendors.

It's true that once the OS and eval boards are selected, a BSP has to be created by one of those vendors. This is much further down the line and usually must be well thought out in order for a project to be successful. Working with MontaVista is a pain, though.

Not to be a shill for Cirrus Logic for a moment, but another route that I find interesting is the route that Cirrus is taking with their ARM9 processors. You can download a full BSP for free without having to go through these third party BSP vendors. http://arm.cirrus.com/

Ultimately, a system improperly architected will fail in cost, schedule, and/or reliability. Processor/OS selection is just one of those steps.

One thing you fail to notice is the fact that their even talking about adding a HD-DVD feture means that there is a market for it. Plus, if I remember correctly, the reason the Dreamcast didn't have DVD playback was because, Survey says.... the DVD comunity was a nitch market 'til 1999...

I haven't seen an IC data sheet yet that doesn't have an internal schematic of the IC

Find me an internal schematic for this IC? That would be cool. Thanks.

Try to find internal schematics for even simple ICs like LCD controllers or audio chip. And no, block diagrams dont count as internal schematics.

Hell, you can't even find internal schematics for AC97 DACs.

Cirrus Logic EP9301 eval kit.

My employer, for one. See this here Lead free packaging schedule. We're not completely in production yet, but are making our way there.

TCP/IP Lean by Jeremy Bentham, ISBN: 1-929629-11-7

Cirrus Logic CS8900a Ethernet module, it works in 8-bit mode

Buy a CS8900 module.

** Shameless plug **
Read my thesis about how to put it all together.

Many of the current MCUs are ball grid array (BGA) devices, which make them pretty hard to work with if you're not a professional, but a few can be had in PLCC or QFP packages, which means you can get an adapter board or socket.

You can also buy preassembled demo/development boards (this is the route I'm taking) and wire-up anything the board doesn't include by hand. Most of the MCUs on the market will have 32-bit memory busses (though they may not support more that 25 or 26 address lines), so you can attach just about anything you want to them.

This is exactly the kind of thing that Steve Ciarcia (of Ciarcia's Circuit Cellar) used to do: building personal computers from microcontrollers. Most of his designs used Z80 based devices, which was fine back in the mid- to late-eighties. Now, however, you can do a fair bit better.

As for speed, I don't know exactly what you're looking for, but the ARM devices can be had in speeds from 50MHz to 400MHz, and the same is true of the PPC and MIPS devices. That may not seem like much, compared to a 2GHz Pentium, but it's really quite nice.

Some good resources: Digi-Key is a reasonable source for all sorts of parts, Atmel makes some nice MCUs, programmable logic, and Flash RAM, Cirrus Logic makes some ARM MCUs and networking chips (amoung other things), Sharp, Samsung, Motorola, and AMD all make nice MCUs, Cogent Computers builds some nice development boards, and EarthLCD has good prices on LCDs and has an ARM based board in the works.

Well, if someone was serious about it. The Crystal/Cirrus CS8900A has an 8-bit interface mode. There are a number of projects on the web interfacing it to several 8-bit processors. Someone could conceivably make a cartridge containing an ethernet interface and the Contiki Desktop in ROM (I'm not holding my breath though).

It's a Cirrus EP7212 (I think, may be a 7312). Anyway, 74MHz ARM720T, memory controller, dual RS232 UART, dual audio CODEC interfaces, LCD, RTC, serial bootstrap (all you need to do the initial flash load is access to the UART0 RS232), and power management. Linux runs on these, as well as a bunch of other RTOSes.

I will be thrilled if a complete EP9312 based system ends up being so inexpensive that it forces the price down on the other stuff.

What you really want is one of these.

Dual EtherMACs, triple host USB ports, phat FPU, audio, VGA/LCD/TV, 200MHz ARM920T core. It's supposed to cost less than this MCM kludge and be available sooner. Did I mention that it will run Linux?

Creative soundcards aren't good, they're good enough. Without competition there really isn't any way to judge 'better' or 'worse'.

There are plenty of other sound card manufacturers out there. Look at AOpen, Crystal and Analog Devices. They all make sound cards, but why are they not leading the market? Because Creative cards are just plain better.

I have never had problems installing a Creative card. Plus, they are still improving their cards (even when they don't have to). The new series of Live cards prove this. They are amazingly above their old Live series and the competition. I have tried the other cards, and my judgement is that Creative leads the market because their products are insanely superior to the competition. Besides...how much more can one add on to a sound card???

I don't know what you are using for your MP3 decode, but if you wanted a really easy solution try using the Cirrus Logic EP9312 ARM9. It has built in EIDE, USB, LCD interface logic, kepad scanner, etc and can run embedded Linux. Of course this might be to easy of a solution for you (almost everything on one chip).

That's about all i have to add.

From the page: UK-based Alba chose Cirrus Logic's PS7500FE device because it provides a highly-integrated solution that combines major system components onto a single chip. The PS7500FE incorporates a 32-bit ARM RISC processor with advanced peripheral functions, including a floating point co-processor, a display controller, a complete memory controller, and direct interfaces to modem and LAN devices.

For a player that fits into the world envisioned by Thomson & Fraunhofer IIS-A, it's really not that expensive to make a cool MP3 player...
<shameless plug>
...like this one that I've been working on lately.
</shameless plug>

Ahh, the sweet memories...

--
Kiro

Writing your own player firmware is not easy. I bought a copy of ISO 11172-3 (the MPEG1 audio spec), and it's quite complicated. There are lots of open source players, but they all use floating point math, because it's so much easier and runs fine on any modern PC. Maybe I'll write this someday. If I do, I'll GPL it.

For now, I'm not using this EP7209 chip right now, mainly because it's in a 208 pin high density surface mount package, and one of the goals of my homebrew MP3 player project is to offer a design and components that an average electronics hobbist can build.

Of course, it'll be a challenge to make the existing decoder chips (MAS35077D and STA013) SDMI compliant, since they don't interact with the user, so they could only see the trigger and perhaps tell the microcontroller chip to prompt the user. Since these chips lack non-volatile memory (and probably always will), any player like mine that is open source will allow the user to interact with the chip however they like.

I doubt they'll manage to make these chips SDMI compliant in any meaningful way, but it's still a very scary thought... this guy's obviously in bed with the RIAA and maybe he's just speculating, or maybe he knows something?

bc

Hmmpf. Well, while waiting for the crowd to die down here's the skinny on a cirrus MP3 DEcoder in Si.

I've been real happy w/ bladenc, but haven't tried any others.

Chuck