Author Topic: 8-bit uC - is there even a point?  (Read 27511 times)

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Offline langwadt

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Re: 8-bit uC - is there even a point?
« Reply #275 on: October 05, 2018, 09:28:58 pm »
Anything that runs off 5V.

Turning that around and looking at starting requirements from the other end of the telescope, what if you want true 5V outputs and nott just 5V tolerant and must have 32 bit core?
I know of:
  Cypress PSOC4 arm cortex m0
  Cypress PSOC5 arm cortex m3
  Atmel/Microchip SAMC21     automotive series cortex m0 these are nice because additionally they are one of the few mcu that have CAN FD

Are there any others? including obscure non-arm 32 bitters?


afaik Freescale, now NXP, has a bunch of Cortex-M and PowerPC for automotive that are 5V supply and IO

 

Offline chickenHeadKnob

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Re: 8-bit uC - is there even a point?
« Reply #276 on: October 05, 2018, 09:35:57 pm »
Quote from: coppice
Motorola developed two cores - the CPU16 (the core in the 68HC16) and the CPU32 (based on the 68000 core) - at the same time, intending to mix and match a set of modular peripherals and these two cores to suit a wide range of needs. It turned out most people were either OK with Motorola's existing HC05/HC08 or HC11 cores, or needed the performance of the CPU32.
moto HC05. Yuck. Any youngling that still yearns for the 8 bit era should be forced, as I was, to program these register starved memory deficient craptastic things. That will cure you.
The HC05 was one of the most successful MCU families. It was a key part of what made Motorola the biggest MCU maker in the world.

Oh I have first hand experience with the popularity part as well. Some time after Moto bought or merged with GM-Hughes the auto sector snarfed up all available supply and they went on allocation. Couldn't get one for love or money, almost sank/bankrupted  the small manufacturer I was working for.
 

Offline coppice

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Re: 8-bit uC - is there even a point?
« Reply #277 on: October 05, 2018, 09:48:11 pm »
Quote from: coppice
Motorola developed two cores - the CPU16 (the core in the 68HC16) and the CPU32 (based on the 68000 core) - at the same time, intending to mix and match a set of modular peripherals and these two cores to suit a wide range of needs. It turned out most people were either OK with Motorola's existing HC05/HC08 or HC11 cores, or needed the performance of the CPU32.
moto HC05. Yuck. Any youngling that still yearns for the 8 bit era should be forced, as I was, to program these register starved memory deficient craptastic things. That will cure you.
The HC05 was one of the most successful MCU families. It was a key part of what made Motorola the biggest MCU maker in the world.

Oh I have first hand experience with the popularity part as well. Some time after Moto bought or merged with GM-Hughes the auto sector snarfed up all available supply and they went on allocation. Couldn't get one for love or money, almost sank/bankrupted  the small manufacturer I was working for.
That would have been around 1994 or 1995, right? The issue wasn't acquisitions. They badly screwed up resource allocation across the board. Sales grew faster than they could scale their factories. Efforts to use outside fabs hit many stumbling blocks. Combine this with the fact that the needs of Motorola communications always came first, and everything else a poor second. They had a lot of angry customers who really liked a Motorola chip but were suddenly unable to get quantities of it as they reached mass production. The backlash from this is a big part of why Motorola fell from their number 2 position in the semiconductor world.
 

Offline legacy

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Re: 8-bit uC - is there even a point?
« Reply #278 on: October 05, 2018, 10:04:11 pm »
[..] HC11 cores, or needed the performance of the CPU32.

Indeed all the boards I have seen in micro-robotics are boards are either hc11 (e.g. HB by MIT) or 683xx (e.g. MR by MIT); never seen hc16, but I know it existed. The question is ... who used it? And for what?

HC12 comes with a fuzzy-engine that is missing on both HC11 and 683XX, but the HC16 has it.
 

Offline chickenHeadKnob

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Re: 8-bit uC - is there even a point?
« Reply #279 on: October 05, 2018, 10:45:19 pm »

That would have been around 1994 or 1995, right? The issue wasn't acquisitions. They badly screwed up resource allocation across the board. Sales grew faster than they could scale their factories. Efforts to use outside fabs hit many stumbling blocks. Combine this with the fact that the needs of Motorola communications always came first, and everything else a poor second. They had a lot of angry customers who really liked a Motorola chip but were suddenly unable to get quantities of it as they reached mass production. The backlash from this is a big part of why Motorola fell from their number 2 position in the semiconductor world.

No a decade earlier, 1984-85. Not long after the plastic dip one-time programmable 6805 first came out. There were actually many boom-bust shortages with motorola, but the one that I was remembering was caused by auto makers starting to use  the parts big time.
 

Offline GeorgeOfTheJungle

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Re: 8-bit uC - is there even a point?
« Reply #280 on: October 05, 2018, 11:00:03 pm »
That's the birth of ECUs, when cars were moving from carburetor to EFI.
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Offline chickenHeadKnob

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Re: 8-bit uC - is there even a point?
« Reply #281 on: October 05, 2018, 11:42:24 pm »
That's the birth of ECUs, when cars were moving from carburetor to EFI.

Only sort of contemporaneous, there were already  ECUs designed in 82 or so. Typically either an 8051 or intel 8096. I am reasonably certain the 8096 was designed initially for a Robert Bosch ECU. The first 8051 ECUs were not fast enough for control loop every revolution, instead had averaged control. I don't think anyone used a 6805 for engine control but could be wrong. It was the start of a massive influx of mcu's in other secondary control circuits, from radios to what-ever. The first antilock brakes were already common but the first generation was not done with digital control. It was some type of analog mechanical mechanism. Then Motorola came out with the 68xxx around 1986, can't remember the part number but it was the initial mcu that offered the crazy complicated 4 channel timer control unit,  before the first coldfires. The motorola  app-engineer taunted us in a seminar "guess what application and customer those timer channels are for"
 

Offline langwadt

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Re: 8-bit uC - is there even a point?
« Reply #282 on: October 05, 2018, 11:53:48 pm »
That's the birth of ECUs, when cars were moving from carburetor to EFI.

Only sort of contemporaneous, there were already  ECUs designed in 82 or so. Typically either an 8051 or intel 8096. I am reasonably certain the 8096 was designed initially for a Robert Bosch ECU. The first 8051 ECUs were not fast enough for control loop every revolution, instead had averaged control. I don't think anyone used a 6805 for engine control but could be wrong. It was the start of a massive influx of mcu's in other secondary control circuits, from radios to what-ever. The first antilock brakes were already common but the first generation was not done with digital control. It was some type of analog mechanical mechanism. Then Motorola came out with the 68xxx around 1986, can't remember the part number but it was the initial mcu that offered the crazy complicated 4 channel timer control unit,  before the first coldfires. The motorola  app-engineer taunted us in a seminar "guess what application and customer those timer channels are for"

I think Motorola and GM did an ECU sometime in the mid 70's based on 6502

 

Offline coppice

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Re: 8-bit uC - is there even a point?
« Reply #283 on: October 06, 2018, 12:42:10 am »
That's the birth of ECUs, when cars were moving from carburetor to EFI.

Only sort of contemporaneous, there were already  ECUs designed in 82 or so. Typically either an 8051 or intel 8096. I am reasonably certain the 8096 was designed initially for a Robert Bosch ECU. The first 8051 ECUs were not fast enough for control loop every revolution, instead had averaged control. I don't think anyone used a 6805 for engine control but could be wrong. It was the start of a massive influx of mcu's in other secondary control circuits, from radios to what-ever. The first antilock brakes were already common but the first generation was not done with digital control. It was some type of analog mechanical mechanism. Then Motorola came out with the 68xxx around 1986, can't remember the part number but it was the initial mcu that offered the crazy complicated 4 channel timer control unit,  before the first coldfires. The motorola  app-engineer taunted us in a seminar "guess what application and customer those timer channels are for"

I think Motorola and GM did an ECU sometime in the mid 70's based on 6502
I doubt that Motorola used a 6502. Using any NMOS in the mid 70s was a big problem for a car engine. NMOS would only operate a few degrees below zero. It didn't take much cooling to make MPUs of the time, like the 6800 and 8085, crash. TI and others put a lot of effort into IIL versions of their processors, because it was a technology that worked over a wide temperature range. Eventually, the temperature range of MOS processes improved, but only a few suppliers, like Motorola and Hitachi, really got to grips with the qualification needs of the automotive industry. The cost structure of IIL was never really sorted out, and it quickly faded away.
 

Offline langwadt

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Re: 8-bit uC - is there even a point?
« Reply #284 on: October 06, 2018, 01:09:11 am »
That's the birth of ECUs, when cars were moving from carburetor to EFI.

Only sort of contemporaneous, there were already  ECUs designed in 82 or so. Typically either an 8051 or intel 8096. I am reasonably certain the 8096 was designed initially for a Robert Bosch ECU. The first 8051 ECUs were not fast enough for control loop every revolution, instead had averaged control. I don't think anyone used a 6805 for engine control but could be wrong. It was the start of a massive influx of mcu's in other secondary control circuits, from radios to what-ever. The first antilock brakes were already common but the first generation was not done with digital control. It was some type of analog mechanical mechanism. Then Motorola came out with the 68xxx around 1986, can't remember the part number but it was the initial mcu that offered the crazy complicated 4 channel timer control unit,  before the first coldfires. The motorola  app-engineer taunted us in a seminar "guess what application and customer those timer channels are for"

I think Motorola and GM did an ECU sometime in the mid 70's based on 6502
I doubt that Motorola used a 6502. Using any NMOS in the mid 70s was a big problem for a car engine. NMOS would only operate a few degrees below zero. It didn't take much cooling to make MPUs of the time, like the 6800 and 8085, crash. TI and others put a lot of effort into IIL versions of their processors, because it was a technology that worked over a wide temperature range. Eventually, the temperature range of MOS processes improved, but only a few suppliers, like Motorola and Hitachi, really got to grips with the qualification needs of the automotive industry. The cost structure of IIL was never really sorted out, and it quickly faded away.

6802

http://www.chipsetc.com/computer-chips-inside-the-car.html
 

Offline coppice

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Re: 8-bit uC - is there even a point?
« Reply #285 on: October 06, 2018, 01:25:01 am »
That's the birth of ECUs, when cars were moving from carburetor to EFI.

Only sort of contemporaneous, there were already  ECUs designed in 82 or so. Typically either an 8051 or intel 8096. I am reasonably certain the 8096 was designed initially for a Robert Bosch ECU. The first 8051 ECUs were not fast enough for control loop every revolution, instead had averaged control. I don't think anyone used a 6805 for engine control but could be wrong. It was the start of a massive influx of mcu's in other secondary control circuits, from radios to what-ever. The first antilock brakes were already common but the first generation was not done with digital control. It was some type of analog mechanical mechanism. Then Motorola came out with the 68xxx around 1986, can't remember the part number but it was the initial mcu that offered the crazy complicated 4 channel timer control unit,  before the first coldfires. The motorola  app-engineer taunted us in a seminar "guess what application and customer those timer channels are for"

I think Motorola and GM did an ECU sometime in the mid 70's based on 6502
I doubt that Motorola used a 6502. Using any NMOS in the mid 70s was a big problem for a car engine. NMOS would only operate a few degrees below zero. It didn't take much cooling to make MPUs of the time, like the 6800 and 8085, crash. TI and others put a lot of effort into IIL versions of their processors, because it was a technology that worked over a wide temperature range. Eventually, the temperature range of MOS processes improved, but only a few suppliers, like Motorola and Hitachi, really got to grips with the qualification needs of the automotive industry. The cost structure of IIL was never really sorted out, and it quickly faded away.

6802

http://www.chipsetc.com/computer-chips-inside-the-car.html
That page says they deployed the ECU in 1981. That was about the time when MOS parts specified down to -40C or -55C were getting to volume production.
 

Offline PCB.Wiz

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Re: 8-bit uC - is there even a point?
« Reply #286 on: October 06, 2018, 02:48:23 am »

Turning that around and looking at starting requirements from the other end of the telescope, what if you want true 5V outputs and not just 5V tolerant and must have 32 bit core?
I know of:
  Cypress PSOC4 arm cortex m0
  Cypress PSOC5 arm cortex m3
  Atmel/Microchip SAMC20 and 21     automotive series cortex m0+ these  additionally are one of the few mcu that have CAN FD

Are there any others? including obscure non-arm 32 bitters?

Sure, but not nearly as wide a choice as 3v.
Fujitsu  (now part of Cypress)  had some 5V ARM, Freescale do a few 5V ARM, and Nuvoton have a wide selection, including 5v M4 parts, Infineon have 5V in M0 parts, and numerous Asian vendors have 5V ARMs in their stables.

Nuvoton also do one of the best-value/cheapest 8 bitters in the N76E003  ~ 25c, for 18k Flash, 1KRAM 12b ADC  16MHz
 

Offline Psi

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Re: 8-bit uC - is there even a point?
« Reply #287 on: October 06, 2018, 09:32:35 am »
If there's still a need for 4 bit micros in cheap electronics (which there is) then there's definitely still a need for faster 8 bit micros.  :-DD
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Offline Kjelt

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Re: 8-bit uC - is there even a point?
« Reply #288 on: October 06, 2018, 11:00:21 am »
Sure in toys costing $2 sales price or perhaps some chinese dimmable ledlamps, they have 4 bit uC in them costing $0,08 in large quantities.
Silly but yes every micro you can buy in the official retail chain today still has its market somewhere, if not it will dissapear.
 

Online Fungus

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Re: 8-bit uC - is there even a point?
« Reply #289 on: October 06, 2018, 04:44:24 pm »
Anything that runs off 5V.
Turning that around and looking at starting requirements from the other end of the telescope, what if you want true 5V outputs and not just 5V tolerant and must have 32 bit core?

I really don't see the relevance of the number of bits in the core.   :-//

Has it got enough pins/timers/serial/I2c/whatever? Use it.
 

Online nctnico

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Re: 8-bit uC - is there even a point?
« Reply #290 on: October 06, 2018, 04:47:43 pm »
BTW: who is still making 5V designs nowadays anyway? Seems more like an old habit than a necessity.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online wraper

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Re: 8-bit uC - is there even a point?
« Reply #291 on: October 06, 2018, 04:50:50 pm »
BTW: who is still making 5V designs nowadays anyway? Seems more like an old habit than a necessity.
If you mix analog and digital, or for directly driving MOSFET gates it can be quite useful. Or when directly powered from lithium battery.
« Last Edit: October 06, 2018, 04:52:25 pm by wraper »
 

Offline analogo

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Re: 8-bit uC - is there even a point?
« Reply #292 on: October 06, 2018, 04:53:55 pm »
BTW: who is still making 5V designs nowadays anyway? Seems more like an old habit than a necessity.

The whole world because of USB?
 

Offline coppice

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Re: 8-bit uC - is there even a point?
« Reply #293 on: October 06, 2018, 05:14:35 pm »
BTW: who is still making 5V designs nowadays anyway? Seems more like an old habit than a necessity.
For noisy environments, like automotive, white goods and motor control, 3.6V and lower voltage designs are much less robust that a similar 5V design would be. Most new designs do use lower voltages, because the designers have little choice. They don't like it, though, and they end up with longer design cycles trying to get their designs rock solid.
 

Online nctnico

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Re: 8-bit uC - is there even a point?
« Reply #294 on: October 06, 2018, 05:27:17 pm »
BTW: who is still making 5V designs nowadays anyway? Seems more like an old habit than a necessity.
The whole world because of USB?
But you wouldn't use 5V USB power directly anyway because the cables and connectors can have a significant voltage drop. Using an LDO to get to 3.3V is a much safe bet.
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online wraper

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Re: 8-bit uC - is there even a point?
« Reply #295 on: October 06, 2018, 05:32:18 pm »
BTW: who is still making 5V designs nowadays anyway? Seems more like an old habit than a necessity.
The whole world because of USB?
But you wouldn't use 5V USB power directly anyway because the cables and connectors can have a significant voltage drop. Using an LDO to get to 3.3V is a much safe bet.
Most modern "5V" MCUs can work in wide voltage range. Therefore it's a non issue.
 

Online Fungus

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Re: 8-bit uC - is there even a point?
« Reply #296 on: October 06, 2018, 05:44:00 pm »
BTW: who is still making 5V designs nowadays anyway? Seems more like an old habit than a necessity.

"5V" AVR chips (for example) work down to 1.8V, no problem. Use 3.3V if you want to.  :-//


 

Offline KL27x

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Re: 8-bit uC - is there even a point?
« Reply #297 on: October 06, 2018, 05:51:09 pm »
Quote
I understood that QFN is actually one of the most reliable packages from a mechanical point of view. I think I read about this in a paper somewhere, but I don't think I'd be able to find that again. I stand to be corrected.
Wraper might have more info on this. I googled it after he claimed that you want to "float" a QFN off the board while hand-soldering on a specific thickness of solder because of thermal cycling. The first study/paper I found showed that QFN could have MTF of only 3000 cycles of going from something stupid like -30C to 100C. QFP might have MTF of 30,000 in same test. Also it was dependent on how big the die is compared to the package size, since the epoxy in the chip has a coefficient of expansion fairly similar to FR-4. So a tiny die would be better able to withstand flex from temp change in a given package size. And if you follow that logic, any QFN available in two different sizes, the larger might be more robust in this regard.

Quote
QFN is reliable, so long as you have soldermask spacing, e.g. not pad flat to copper with no gap for the solder, this gives it some distance to keep forces inside the elastic zone of deformation. similar to BGA, if you didn't have the balls at the right height they just rip pads off either the chip of the board when flexed

The study I read about it said the exact opposite at least for thermal expansion/contraction. Any soldermask under the chip will expand/contract at a different rate and will put stress on the joints, shortening MTF from thermal cycles.

As far as board flex, maybe you are right. That the more the solder thickness/height the better, and soldermask would not be an issue in absence of extreme temp cycling.
« Last Edit: October 06, 2018, 06:15:43 pm by KL27x »
 

Online nctnico

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Re: 8-bit uC - is there even a point?
« Reply #298 on: October 06, 2018, 05:53:24 pm »
@Fungus:
Did you actually try to use a 1.8V Atmel device at 1.8V? I know for a fact it won't work reliable because it is the absolute minimum voltage. A few tens of millivolts less and you'll see devices starting to fail in subtile ways. Also do you want to run a microcontroller circuit from a wildly varying supply voltage? Sounds like a recipy for dissaster to me.

From my experience a very good design rule is not to use external voltages directly for supplying (digital) circuits because you never know what may happen to them. Better generate all supply voltages on the same board.
« Last Edit: October 06, 2018, 05:56:33 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online Fungus

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Re: 8-bit uC - is there even a point?
« Reply #299 on: October 06, 2018, 06:15:24 pm »
@Fungus:
Did you actually try to use a 1.8V Atmel device at 1.8V? I know for a fact it won't work reliable because it is the absolute minimum voltage.
Never done it myself but I've run plenty of them off CR2032s (which can easily dip down to 2.0V under any load).

A few tens of millivolts less and you'll see devices starting to fail in subtile ways.

Are you sure you had the 'V' designated chips? If it's really a problem then aim for 1.9V, sorted.

My only point was that calling it a 5V part is incorrect. That's only the maximum.
 


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