5 ms·
These have their uses. A friend who frequently does contract development in the toy space has (or at least used to have) a favorite go-to MCU that costs under
by dbcurtis 7y ago
These have their uses.
A friend who frequently does contract development in the toy space has (or at least used to have) a favorite go-to MCU that costs under $0.06 in bare die. It is essentially a 6502 with 100 bytes of RAM and a metric butt-load of mask-programmable ROM. It was originally designed for greeting cards. He has designed it into toys.
It is hard to use, you need a dev kit and a good relationship with the distributor to get the documentation. It only makes sense in high-volume products, since it comes as passivated bare die so assembly requires a die-bonder and expoxy encapsulation depositer.
Not for everyday use. But as my friend says: “You haven’t lived until you have spent an entire afternoon arguing over $0.05 on the BOM.”
- bobjordan 7y agoGreat story, thanks for sharing. I for one pretty much constantly live the life he alludes to at my company bomquote.com. In China, we actually negotiate in increments of ~1/6th of a penny.
- Scoundreller 7y agoWhy not a tenth?
- fheld 7y agoI guess the 1/6 comes from a currency conversion
- ssalazar 7y agoThe yuan-usd exchange rate has floated around 6:1 until recently, with yuan denominated down to 0.01. So possibly that.
- bobjordan 7y agoNailed it. https://en.wikipedia.org/wiki/Jiao_(currency) https://en.wikipedia.org/wiki/Jiao_(currency)
- eecsninja 7y agoDon't you mean fen? https://en.wikipedia.org/wiki/Fen_(currency) https://en.wikipedia.org/wiki/Fen_(currency) 1/6 of a penny is 0.0016 USD, or 0.01 CNY: https://www.google.com/search?q=0.0016+usd+to+cny https://www.google.com/search?q=0.0016+usd+to+cny
- MarcPereira 7y agoIt´s very common to find those chips in cheap home alarm systems. In Brazil, Holtek has a huge presence in that niche.
- benj111 7y ago"metric butt-load of mask-programmable ROM" What would that be in this context? I'm guessing we're talking KB rather than TB?
- jacobrobbins 7y agothe poster mentioned it was for greeting cards, I remember their used to be a lot of greeting cards that would play a recording when you opened them. I bet they loaded low-quality samples into the ROM for that.
- vardump 7y agoI'd guess about 1 MB order of magnitude. That would be a butt-load even for samples. 1 MB would be enough for 45 seconds audio at 8 bit PCM @22 kHz. If they're half competent, they could use ADPCM or much better (and cheaper to decode too!) vector quantization. With VQ, you could go even down to ~1 bits (~6 minutes of audio per megabyte) per sample while maintaining good audio quality. Decoding is very simple, so 6502 would have plenty of oomph to do that.
- childintime 7y ago> [Vector quantization] Decoding is very simple. Do you have an encoder/decoder to point us to?
- vardump 7y agoVQ is a very well known technique. For something quick, you might be interested to check this blog post about (unmodified) C64 playing high quality audio at 44.1/48 kHz, VQ compressed down to 96-128 kbit/s: https://brokenbytes.blogspot.com/2018/03/a-48khz-digital-music-player-for.html https://brokenbytes.blogspot.com/2018/03/a-48khz-digital-mus... There's some decoder code there as well.
- enthdegree 7y agoArithmetic coded uniform quantization works very well and is straightforward to implement!
- jerryr 7y agoThat sounds very similar to my experience with toy development. For a toy that played a bunch of pre-recorded sounds, we used a 4-bit Winbond MCU (their MCU division is now Nuvoton) that had a tiny bit of RAM and a ton of mask ROM. Firmware development was done in assembly and targeted a huge (physically large) emulator for test/debug. When we were satisfied with the firmware, we'd send it off to our CM, who would then order the parts with our FW in ROM. They'd get back bare die parts, which were wire bonded to the PCB and then epoxied over (that miserable "glop top" packaging, which is the bane of many teardowns). Development was a bit painful, but high volume production was extremely cheap. Edit: Oops. I conflated projects. The toy project actually used a SunPlus MCU, not a Winbond MCU. It was an 8-bit RISC CPU running at 5MHz with 128 bytes RAM and 256KB mask ROM. The ROM held both the program and audio samples. I don't recall what encoding was used for the audio.
- nickpsecurity 7y agoWell, I'm curious which project used a 4-bitter. Jack Gansle and Robert Cravatta did a survey a while back: http://www.embeddedinsights.com/channels/2010/12/10/considerations-for-4-bit-processing/ http://www.embeddedinsights.com/channels/2010/12/10/consider... http://www.ganssle.com/rants/is4bitsdead.htm http://www.ganssle.com/rants/is4bitsdead.htm The two examples were timepiece designs and Gilette Fusion ProGlide. On top of getting yours, I'm curious if any of these cheap MCU's in the article could today have met whatever your requirements were for a 4-bitter?
- jerryr 7y agoIt was also for a low-cost audio application, but it wasn't a toy. This was back in 2001 or so. The MCUs in this article all only have ~1KB ROM, which wouldn't have been enough for our audio samples. We needed >256KB. The "4-bitness" was just incidentally what Winbond offered with a large ROM at the time. However, the SunPlus that we later used in the toy also offered a large ROM with an 8-bit CPU for a similar cost. So, while I can't authoritatively say that 4-bit is dead, it does seem like there are a lot of alternatives in similar price ranges now.
- somesortofsystm 7y ago>6502 Without question, one of the nicest platforms to have in multitudes of thousands, at low energy and cost ..
- kragen 7y agoHonestly I'd prefer an ARM or an 8086 or an AVR. I imagine I'd prefer a J1A too but haven't tried. The 6502 makes it a pain to do anything in any language higher-level than assembly, even C, and being 8-bit means you're constantly facing tradeoffs between making things fast or making them correct for more than 128 or 256 items.
- nsxwolf 7y agoIs a "expoxy encapsulation depositer" the thing that makes those black blobs?
- Taniwha 7y agoYes - but more it's two machines - the one that place the raw die on the board then stitches the bonding wires, and the one that throws the epoxy blob on top of that
- andrehacker 7y agoAh, yes, there was an article here a year back about the original Furby using that same configuration. The article actually had the annotated 6502 source code. https://news.ycombinator.com/item?id=17751599 https://news.ycombinator.com/item?id=17751599
- tomcam 7y agoAmazing numbers. Can you give me a more accurate number than metric buttload? Closer to 8K or 64K, for example?