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FarmerPotato

What if? Designing "Geneve 2020". Cool 3D views!

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Because I plan on using my TI stuff, for 30 more years, I'll pay for machine screw sockets - every single time! 😃

One of the things I love about SNUG boards, Michael Becker, made them to last.

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Posted (edited)
On 5/10/2021 at 6:43 AM, Ksarul said:

This is one of the main reasons I generally sell my boards assembled--it allows bulk buys for most of the parts, significantly reducing the build cost and keeping the board prices reasonable.

I took a look at my BOM so far. Bulk savings looks like 8% on the big items. But there are real savings from shipping charges: there are a dozen sources.

 

Bad news for me:  I was shocked to discover parts that are out of stock!

 

  • iCE40HX4K-TQ144 is out of stock for a year maybe! This is the only non-BGA version of my FPGA. I can substitute the iCE40LP (or LM) and probably the 1K size. But those are also scarce. My little stockpile was 3 chips, now down to 1.

 

I am seeing the semiconductor crunch on multiple fronts. (It's not so much a shortage, as an increase in demand.)

 

  • A dev board, that I was eyeing, is now unobtainable. I placed a back order at the 20% higher price.

 

  • The audio amplifier part, OPA1688: 10K stock vanished while I took a week to simulate the circuit in PSPICE.

 

  • TMS99105. (eBay) Qsourceco_6 was my preference for new old stock at $33 each/$30 bulk. Now they are $40 for qty and $48 singly. (eBay) Polida2008 still offers $33. My stockpile of these is 6 chips. (BTW Qsourceco_6 has a US trove of NOS gold/ceramic chips!)

 

  • Memoryx.com has folded. This was my source for cheap, new, plentiful DRAM.  The new owner of the domain sells memory on eBay, and it is awful. I'm talking about 30-pin SIMMs. Because retro.

 

  • qsourceco_6 has an expensive pile of new XC9572-10TQG100I, 5V tolerant FPGA, hobbyist-friendly, that normally cost $5 new at mouser. But you have to get in line at the distributors.

 

I found MemoryMasters on newegg, they appear to have the same business model, but no good way to find a part. Like memoryx, they also sell 2x16MB for $30. 2x4MB is no longer cheap and 2x1MB is gone. Maybe I'll drop the idea in favor of a boring SDRAM after all.

 

Anyway, today it's back to progressing on the VGA upscaler for the 9958... which depends on that iCE40 part. I checked and (eBay) ic_detective is still selling the other main part I got. But stockpile!

 

All of these surprises are probably solvable, but what a headache.

 

Edited by FarmerPotato
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22 hours ago, dhe said:

Because I plan on using my TI stuff, for 30 more years, I'll pay for machine screw sockets - every single time! 😃

One of the things I love about SNUG boards, Michael Becker, made them to last.

Wait, you prefer machine pin sockets?

 

Those drive me crazy! I broke pins on an EEPROM, while trying to put it back into a machine pin socket.

 

Still, bring your own sockets! Not an issue for me.

 

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Even after many years of use, thermal expansion won't walk the chips out of these sockets.

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Posted (edited)

Audio Block Diagrams

 

I was checking chip availability today, and found an intriguing possibility.

 

So far, this is the current model for the audio card:

 

image.thumb.png.27ddd271763d50d40a65bce4ee248df0.png

 

 

 

Today, I saw that ic_detective has AD1888 chips for $5. This is a full PC AC'97 audio codec, made in 2005. AD1888 could replace a bunch of chips and result in input/outputs like this:

 

 

image.thumb.png.d442b4a37e0545fbdba2204b973ef5e6.png

 

 

With or without putting in all the extra features, the AD1888 saves a lot of hassle. I omitted my extra analog-out patch jacks, which had been a fun idea.

 

 

 

 

Edited by FarmerPotato
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I bought a few TMS99105s from Qsourceco_6 last November, when his prices were lower. I was a bit surprised by the price increases when I went to look at getting a few more this past weekend. . .

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But, you've removed "Phono out". You're not eliminating the stylus?:evil:

...what will people say???:D

 

   P.S. Glad you're keeping-at-it.;-)

 

   P.P.S. For HI-REL, I always solder. ...Otherwise, I, too, swear by machined-pin sockets.:ponder:

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1 hour ago, HOME AUTOMATION said:

But, you've removed "Phono out". You're not eliminating the stylus?:evil:

...what will people say???:D

 

   P.S. Glad you're keeping-at-it.;-)

 

   P.P.S. For HI-REL, I always solder. ...Otherwise, I, too, swear by machined-pin sockets.:ponder:

The stylus is still buried in there, but it only plays 1 millimeter LPs.

 

It's a secret of the AC'97 committee. They didn't want to talk too publicly about it in the 90s. But now phono is cool...

 

 

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Posted (edited)

Working all week on Geneve 2020 -- No kids!

 

Semiconductor shortage update:

 

The dev kit for Lattice ECP5 was delivered today. This isn't related to Geneve 2020. It was for resume building. It is the only inexpensive FPGA development board with PCIe (and it is 3 years old "obsolete"). It is perfect if you want to learn to write a Linux device driver for PCIe. Use any of the peripherals onboard, or build on the prototyping area. The available stock vanished in May, with backorder time 8 weeks, but I got mine after 5 weeks.

 

Lattice FPGA ICE40HX4K-TQFP144 at Mouser are still expected in August, but in small quantities (300). (LM4K and LP4K don't come in hobbyist-friendly TQFP-144, only ball-grid. Must get TQFP package.) The 4K unlocks to 8K in IceStorm, which is terrific. I ordered and received 10 of the 1K parts, which are probably adequate. The VGA up-scaler fits in 1K, so far. 

 

I can use a 1K in each place that FPGA is needed, instead of sharing one big 4K part. Sharing was always going to be awkward, since 3 cards needed the FPGA: dynamic RAM controller/memory mapper, audio (digital mixing, I2S bus to DAC), video (to drive VGA output and new video mode). Substituting 3 1K chips for one 4K chip will add $16 to the bill. (chip+flash+oscillator+voltage regulator) 4K: $6.31 (less than qty 25) 1K: 

 

OPA1688ID, TI audio amplifier:  Digi-Key has none, Mouser has a stub end of a reel of SOIC-8, and lots of unfriendly SON-8 (pads under the package). Some 2,000 coming in June/July, but past stock levels had been 10,000. I have 10. NO PROBLEM: TI.com has lots of SOIC-8 for $1.07.  Also, I've begun soldering SON-type and it's as easy as SOIC-8.

 

CS4334 Cirrus audio DAC. Available at Mouser, for now. Several CS43* out of stock. Restock, including automotive grades, not til December! Been using this chip from the start.  But there are lots of DACs out there from Analog Devices and TI. CS4354 is fine too and cost under $3. Both are TSSOP parts (0.65mm) though.

 

For instance:  PCM1725. For $3.60 direct from TI in qty 1. SOIC-14 (1.27mm) that has I2S interface (like the Cirrus chips) with integrated amp. $6 at Mouser.

 

CS5343 audio ADC. Very little stock. Expected 2022. The ADC function  (mic, line in) is not designed yet anyhow. There's an 8-bit ADC on the YM2608 sound chip too. I think 8 bit is "retro correct", but still, 16-bit stereo samples were common by the 90s.

 

 

OK too much time shopping (and I'm not being considered for the Linux device driver job anymore.) Back to work, I've got 5 glorious days alone.

 

Articles on the semiconductor shortage:

https://semiengineering.com/shortages-challenges-engulf-packaging-supply-chain/

https://arstechnica.com/gadgets/2021/06/chip-shortages-lead-to-more-counterfeit-chips-and-devices/

 

6/18 Update: of the 10 ICE40HX4K-TQFP144  that I ordered, Mouser has allotted me 6 chips in December. They promise me 4 chips in March 2022. They advertise 400 back in stock in March. This tells me that they don't advertise expected shipments that are already spoken for. I infer they may get stock every quarter, but June, September were already sold when I ordered.   I am going ahead with planning the multiple 1K chips. 

 

6/25 Update: Mouser now has higher estimate for December, so I get 10 in December. All told, just 1200 chips available over the next year... Even fewer in the ball-grid packages (scary).

 

7/14 Update:

 

Mouser pushed back availability of the 4K part to March 2022. No parts in December. 

Edited by FarmerPotato
7/22 Update availability
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