Author Topic: mcu price !!!  (Read 6498 times)

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Offline 5282

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mcu price !!!
« on: October 11, 2016, 06:28:39 pm »
st and nxp and atmel make cortex-m4 and cortex-m7 microcontroller
price >6$
and at this price i can buy cortex-a8 1ghz + sdram  chips
why they manufacturing cortex-m4 and cortex-m7 at this price and i can buy high performance cortex-a8 1ghz cpu at same price ????
 

Online ataradov

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Re: mcu price !!!
« Reply #1 on: October 11, 2016, 06:45:20 pm »
why they manufacturing cortex-m4 and cortex-m7 at this price and i can buy high performance cortex-a8 1ghz cpu at same price ????
Because you will also need PMIC for A8 and at least 8-layer board, which are expensive. You will also get higher power consumption, which is not going to work for a lot of systems.
Alex
 

Online blueskull

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Re: mcu price !!!
« Reply #2 on: October 11, 2016, 06:51:05 pm »
To use an A7/A8, you need PMIC, you need Flash+RAM, and none of them is free. Also, OSes running on A7/A8 take longer to boot compared to bare metal M4/M7 programming.
Also, due to the inherent less complicated design, M series is more reliable than A series.
Finally, buying from NXP you know it is made with a constant high quality factor. Buying a chip from a fabless does not guarantee as they cannot control fab process themselves.
 

Online wraper

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Re: mcu price !!!
« Reply #3 on: October 11, 2016, 06:58:43 pm »
Finally, buying from NXP you know it is made with a constant high quality factor. Buying a chip from a fabless does not guarantee as they cannot control fab process themselves.
The fact someone has own fabs does not mean their chips are built there. Especially if those chips have small feature size. IMO their cortex M chips are built at either Globalfoundries or TSMC.
« Last Edit: October 11, 2016, 07:03:34 pm by wraper »
 

Online ataradov

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Re: mcu price !!!
« Reply #4 on: October 11, 2016, 07:04:05 pm »
Also,  what is the source for your pricing? I assume you are looking at some random A8 chip on alibaba and comparing it to DigiKey single quantity pricing?

That's not how you price a real product.
Alex
 

Offline Marco

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Re: mcu price !!!
« Reply #5 on: October 11, 2016, 07:11:05 pm »
You can get Allwinner H3 boards for 8$ in singles, it is indeed getting a bit silly.

It's a shame there are no RTDM drivers (for the realtime co-kernel for Xenomai Linux). It would be an excellent alternative to the more powerful microcontrollers for hobbyists.
 

Online blueskull

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Re: mcu price !!!
« Reply #6 on: October 11, 2016, 07:15:16 pm »
The fact someone has own fabs does not mean their chips are built there. Especially if those chips have small feature size. IMO their cortex M chips are built at either Globalfoundries or TSMC.

You are right. Freescale makes all their MCUs in house, but NXP makes their MCUs off site, usually TSMC. However, NXP-Freescale is moving to in house 28nm SOI for their all new MCU products, including LPC product line, starting from i.MX7.
In fact, NXP-Freescale states that 28nm SOI will be the last simple node (probably they mean 2D gate structure?), and therefore will be extremely long lasting and low cost, just like 0.25um/0.35um process does in analog IC world.
« Last Edit: October 11, 2016, 07:48:43 pm by blueskull »
 

Offline Marco

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Re: mcu price !!!
« Reply #7 on: October 11, 2016, 07:29:32 pm »
In fact, NXP-Freescale states that 28nm SOI will be the last simple node (probably they mean 2D gate structure?)

Probably the lithography (ie. dual patterning is no longer enough). FD-SOI can scale down below 28nm while staying planar.
 

Offline coppice

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Re: mcu price !!!
« Reply #8 on: October 11, 2016, 07:42:46 pm »
The fact someone has own fabs does not mean their chips are built there. Especially if those chips have small feature size. IMO their cortex M chips are built at either Globalfoundries or TSMC.

You are right. Freescale makes all their MCUs in house, but NXP makes their MCUs off site, usually TSMC. However, NXP-Freescale is moving to in house 28nm SOI for their all new MCU products, including LPC product line, starting from i.MX7.
In fact, NXP-Freescale states that 28nm SOI will be the last simple node (probably they mean 2D gate structure?), and therefore will be extremely long lasting and low cost, just like 0.25um/0.35um process does in analog IC world.
What makes you think that NXP-Freescale have an in house 28nm SOI process? I thought they used the STM process, running in a foundry.
 

Offline coppice

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Re: mcu price !!!
« Reply #9 on: October 11, 2016, 07:48:39 pm »
st and nxp and atmel make cortex-m4 and cortex-m7 microcontroller
price >6$
and at this price i can buy cortex-a8 1ghz + sdram  chips
why they manufacturing cortex-m4 and cortex-m7 at this price and i can buy high performance cortex-a8 1ghz cpu at same price ????
Very few Cortex-M4 or M7 devices sell for more than about $3 in quantity, and they need to have lots of stuff on the chip to be that expensive. Most are below $2 and many below $1.

Things can look skewed to the casual observer, as no MCU supplier publishes serious (i.e. high volume) prices, and all people see is inflated small volume prices at DigiKey and their ilk. The Cortex-A series market has created a different dynamic, where small quantities are available for a relatively small multiplier over the high volume price.
 

Online blueskull

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Re: mcu price !!!
« Reply #10 on: October 11, 2016, 07:49:19 pm »
What makes you think that NXP-Freescale have an in house 28nm SOI process? I thought they used the STM process, running in a foundry.

Didn't read the whole article. You are right, they are using Samsung's 28nm process.
http://www.eetimes.com/document.asp?doc_id=1328712
 

Online ataradov

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Re: mcu price !!!
« Reply #11 on: October 11, 2016, 07:55:46 pm »
You can get Allwinner H3 boards for 8$ in singles, it is indeed getting a bit silly.
Can you get it for the next 5-10 years?

more powerful microcontrollers for hobbyists.
Why do you care about the price this much as a hobbyist?
« Last Edit: October 11, 2016, 08:24:02 pm by ataradov »
Alex
 

Offline Marco

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Re: mcu price !!!
« Reply #12 on: October 11, 2016, 08:14:07 pm »
I know linux, being able to ssh into a familiar environment is nice. Alas, the Pi's of the world are very far removed from real time.
 

Offline JS

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Re: mcu price !!!
« Reply #13 on: October 11, 2016, 11:47:34 pm »
st and nxp and atmel make cortex-m4 and cortex-m7 microcontroller
price >6$
and at this price i can buy cortex-a8 1ghz + sdram  chips
why they manufacturing cortex-m4 and cortex-m7 at this price and i can buy high performance cortex-a8 1ghz cpu at same price ????

  Why would someone make cats if there are cheaper dogs?  :P

  Other than that, µC and µP are different type of beasts, for different purposes, price and computational power aren't the only two factors, as mentioned power consumption, connectivity, ease of use, are other factors to consider. You may find and M3 or M4 under the seat of your car just to adjust the position, it has the required peripherals in the chip, probably could be done with an M0 but for some reason they found M4 a better option, for example already used 40 times in the same car but the M0 won't cut most of those applications.

JS
If I don't know how it works, I prefer not to turn it on.
 

Offline 5282

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Re: mcu price !!!
« Reply #14 on: October 12, 2016, 03:55:45 pm »
Quote
Because you will also need PMIC for A8 and at least 8-layer board, which are expensive. You will also get higher power consumption, which is not going to work for a lot of systems.

LQFP-176 a13 cortex-a8 1ghz cpu can be routed in 2layer diy pcb at very low cost

a13+pmic+sdram+nandflash cost will be under 6$  in 5pc minimum quantity
but cortex-m4 will cost 6$  in 5pc minimum quantity

quad core cortex-a7 development board will cost 10$ at 1pc
cortex-m4 development board will cost 15$ at 1pc

« Last Edit: October 12, 2016, 04:00:52 pm by 5282 »
 

Offline Monkeh

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Re: mcu price !!!
« Reply #15 on: October 12, 2016, 03:58:01 pm »
LQFP-176 a13 cortex-a8 1ghz cpu can be routed in 2layer diy pcb
a13+pmic+sdram cost will be under 6$  in 5pc minimum quantity
but cortex-m4 will cost 6$  in 5pc minimum quantity

And how in the hell do you expect to connect DDR3 on a 2-layer PCB?
 

Online ataradov

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Re: mcu price !!!
« Reply #16 on: October 12, 2016, 04:37:30 pm »
LQFP-176 a13 cortex-a8 1ghz cpu can be routed in 2layer diy pcb at very low cost
No, it can not.

Also, what chip are we talking about?

Show us the source of your pricing information.
« Last Edit: October 12, 2016, 04:40:38 pm by ataradov »
Alex
 

Offline senso

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Re: mcu price !!!
« Reply #17 on: October 12, 2016, 06:22:05 pm »
The lowest I have seen was an iMX233 in a 4 layer 5x5cm pcb, and that is already bottom of the barrel..
 

Online blueskull

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Re: mcu price !!!
« Reply #18 on: October 12, 2016, 06:29:19 pm »
And how in the hell do you expect to connect DDR3 on a 2-layer PCB?

It's only 16 bit DDR3, which is considerably easier than 32 bit ones, plus they have ODT compared to older DDR revisions.

Also, what chip are we talking about?
Show us the source of your pricing information.

http://www.ebay.com/itm/like/191609481635?lpid=82&chn=ps&ul_noapp=true
 

Online ataradov

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Re: mcu price !!!
« Reply #19 on: October 12, 2016, 06:33:01 pm »
[url]http://www.ebay.com/itm/like/191609481635?lpid=82&chn=ps&ul_noapp=true[/url]


Ok, that's  $4.99 + $3.00 Shipping == $7.99. Plus some sketchy ebay sale that can go away tomorrow. EDIT: this seller combines shipping, so if you buy more than one, you save some money. But even at $5, it is barely competitive with MCUs.

What about flash, RAM and PMIC?
« Last Edit: October 12, 2016, 06:35:34 pm by ataradov »
Alex
 

Online blueskull

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Re: mcu price !!!
« Reply #20 on: October 12, 2016, 06:48:02 pm »
What about flash, RAM and PMIC?

There are cheap RAM and FLASH chips rebranded by small companies, usually sourced from rejected A-brand chips, that still work at 0~70C temperature range. Micron even does this shit itself.
AW has its own PMIC product lineup dedicated for their ASSPs.
 

Online ataradov

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Re: mcu price !!!
« Reply #21 on: October 12, 2016, 06:49:57 pm »
usually sourced from rejected A-brand chips
Ok, so what you are saying is that you can potentially assemble something from trash, that costs the same as Cortex-M7 MCU from DigiKey. If you want to do that - go ahead, but count me out.
Alex
 
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Online blueskull

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Re: mcu price !!!
« Reply #22 on: October 12, 2016, 07:10:54 pm »
usually sourced from rejected A-brand chips
Ok, so what you are saying is that you can potentially assemble something from trash, that costs the same as Cortex-M7 MCU from DigiKey. If you want to do that - go ahead, but count me out.

Micron dares to start their own subsidiary selling these chips, and Lexar dares to put these rejected flash into their top of the line USB3.0/thunderbolt ssd, then why I can't do the same thing as long as I'm designing consumer electronics?
 

Offline Monkeh

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Re: mcu price !!!
« Reply #23 on: October 12, 2016, 08:38:06 pm »
And how in the hell do you expect to connect DDR3 on a 2-layer PCB?

It's only 16 bit DDR3, which is considerably easier than 32 bit ones, plus they have ODT compared to older DDR revisions.

Sure, it's only a 96-ball BGA. Totally do that with a pillar drill and some rivets.
 

Offline rob77

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Re: mcu price !!!
« Reply #24 on: October 12, 2016, 08:47:10 pm »
forget BGA and 2 layer boards... with 2 layers you can either fan-out the signals or provide power with decoupling but not both at the same time :D
 


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