How Swappable Are I2S Sound Chips? - Page 1
Forum section: electronics / projects

author: starhawk
author_rank: Regular Contributor
timestamp: November 08, 2020, 08:01:12 pm
content: As is often the case, I was fiddling last night with some cheapie eBay electronics... and, as is often the case, I screwed something up that was rather important.I have one of those "ultra thin" 10.1in HDMI/etc LCDs, an older model that claims a required 12vDC supply (I've independently verified that it works fine on 5vDC, which is great for my purposes -- and since then, MicroUSB versions have apparently become rather popular).The onboard LCD controller in my example offloads audio handling to an external chip via I2S, rather than handling it internally. In this case, the codec (?) chip in question is an 8pin, surface-mount ES7134LV. I'm relatively unfamiliar, but given that there are exactly five listings for it on eBay, of which all are international and exactly *one* is in US currency, it wasn't exactly the "popular girl" at its high school. Heh. Unfortunately, in my example, the two output pins sheared off completely when I tried to lift them off the PCB -- the internal audio circuit is incredibly stupid in a number of ways, and I wanted to bypass that.So, as usual, having wrapped myself helically around a cylinder in the fashion of an inclined planeI really need to replace that chip, and I need to do so as quickly and dirt-cheaply as possible. I know jack squat about I2S, though, hence the ask...Ignoring an LCD controller firmware swap (I'm *not* diving that far in!) can I swap the ES7134LV here for *any* chip that takes in I2S data and outputs sound (and can someone suggest one?) or do I need to replace it with another ES7134LV for it to work?

author: ataradov
author_rank: Super Contributor
timestamp: November 08, 2020, 08:31:06 pm
content: I2S protocol itself is universal. The issue with swapping is that many codec chips also have I2C configuration interface, and the registers there are different.But ES7134LV does not have that, so it can be replaced by any other I2S IC. It is better to check that replacement IC supports the same modes, but all of them support most common modes.Finding one with the same pinout may be a challenge.But what's the issue with getting the chip you need? LCSC has them in stockhttps://lcsc.com/product-detail/Codec-ICs_Everest-Semiconductor-ES7134LV_C365745.htmlYou also need to check analog driver characteristics. You need to find a chip that can drive the actual load.

author: starhawk
author_rank: Regular Contributor
timestamp: November 08, 2020, 10:07:32 pm
content: Shipping from there is *incredibly* expensive. I'm used to eBay shipping (ePacket for international, USPS First Class Parcel for most domestic stuff) and Mouser's $5 hobbyist shipping... this is one case where I could be persuaded to spend $8 on domestic Priority Mail but they want $25-$30 for anything other than what I call the "someday maybe" shipping method (i.e., eBay "International Economy" shove-it-on-a-boat, untracked and with no delivery guarantee, but hey if you wait three months you might get it). Screw that.Suffice to say for now that my budget is "the moth in my wallet starved to death" (this has literally happened on one occasion, not kidding... wish I'd thought to take a photo at the time). I'll get into it if I have to, but I can absolutely guarantee from experience that it will derail the thread into a clown show because a lot of people post without thinking critically very well (or really even at all) when things get into personal finance and and the socioeconomics that drive it, particularly in situations like mine.I don't mind pinouts being different, I have a pile of SOP/SOIC-16 to DIP adapter PCBs I can steal one from, wire it up with that. The external driving circuit is the datasheet's reference output circuit, wired to a pair of L386s with a 10k stereo trimpot in between... like I said, the original circuit was stupid. Basically, they wired both outputs together to make a kludgy mono output, then stuffed that in the back end of an SL6699 driver from some company named Li Optoelectronics Tech... (oh, the jokes I could make... not today though!)... it's a stereo chip and yet they're using only the right-side input and output; the output originally went to a speaker that looked like it was from one of those horribly annoying greeting cards that sings to you. Not an expensive one! I ripped it off immediately... I'm no audiophile, and TBH people who spend $300+ on a single pair of headphones annoy me -- some folks have more money than sense, sadly -- but if your speakers are so tinny I'm inclined to think they were made by Cambpell's Soup (hi, every laptop/netbook speaker basically ever) they're going in the spares bin because that stuff makes me cringe hard.So... again, the reference output circuit for the chip, which is (per output side, in order) a series 3.3uF electrolytic cap, a 10K pulldown, a 560R series resistor, and a 3000pF (i.e., 3nF) cap to ground. In my case I'm using three 10nF capacitors in series for the 3nF cap, I figure 3.3nF is probably close enough and it's what I have. Each of those outputs then goes through a 10K stereo trimpot to an LM386's input pin, with a 1500uF 6v3 electrolytic cap in series with the output because the LM386s are getting fed 5vDC and I know that they're not really going to appreciate that... but the less I have to buy, the happier I am. I don't mind a bit of dirty circuit trickery if it gets the job doneEDIT for idiocy lol. Had a brain fart moment, sorry. Do I need to grab a can of Air Wick spray stuff or something? () Anyhow... can you suggest me another chip that I can swap in that's cheap from eBay, preferably domestic? Bonus points if I can find an NOS listing. I'm good at eBay, I'll find the listing, just need something popular is all. Like I said, this is very much unknown territory for me.

author: ataradov
author_rank: Super Contributor
timestamp: November 08, 2020, 10:14:23 pm
content: On my last 6 orders from LCSC maximum shipping cost was $4.91, and minimum $2.21. This is for a standard shipping, which arrives within 20 days. And it does so pretty reliably, they don't use those weird carriers that take months to arrive. But that's up to you, of course.Although last order was at the very end of 2019, so pre-COVID. Things may have become worse.If you can get your hands on some other I2S codec faster and cheaper, then you can try that. But again keep in mind that you need to find one without I2C/SPI configuration interface. The ones with a configuration interface are never configured to just work by default.

author: starhawk
author_rank: Regular Contributor
timestamp: November 08, 2020, 10:16:27 pm
content: Per my (edited) last post, which also details the output config -- please recommend me a few such parts, please, I don't know enough to Google that. (I'm habitually awful at Google anyways.)

author: ataradov
author_rank: Super Contributor
timestamp: November 08, 2020, 10:23:08 pm
content: The only I2S coded that does not have configuration pins that I personally worked with is Cirrus Logic CS4344 -https://www.cirrus.com/products/cs4344-45-48/

author: starhawk
author_rank: Regular Contributor
timestamp: November 08, 2020, 10:32:40 pm
content: Bought four for a little under $12. Not thrilled about the cost, but it's pretty fast and it'll do... that's what I needThanks!