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So you want to build an embedded Linux system? (2020)

jaycarlson.net

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Re: So you want to build an embedded Linux system? (2020)

#11

Post by foxfluff »

blueflow wrote: post #7

I have issues with the section "Microcontroller vs Microprocessor: Differences" Microprocessors are just the CPU, usually with the system bus wired out. Microcontrollers are combined systems, which include a processor and usually some kind of firmware storage and RAM. You can usually differentiate them by whether their pins are address/data lines or gpio-like. > microprocessors have a memory management unit The 8086…

It's a pointless distinction by and large.

Microcontrollers may or may not have storage for firmware. Requiring an off-chip flash is nothing new. Microcontrollers have SRAM, but so do processors. That's where the firmware runs before it gets the DRAM running. Microcontrollers may include a bunch of peripherals, but so do processors. Especially so if you refer to SoCs as processors, like the article here does. And SoCs stir it up further: they have tons of peripherals, and we also have SoCs with on-package DRAM. Discrete SRAM chips exist too, I figured there must be microcontrollers that can use them (but I haven't actually looked).

Yes, the terminology has evolved.

Re: So you want to build an embedded Linux system? (2020)

#12

Post by pjmlp »

gaze wrote: post #4
anthk wrote: post #3

>. In Linux, you get a first-class network stack, plus tons of rock-solid userspace libraries that sit on top of that stack and provide application-level network connectivity. JimTCL is very fun for that, and it would run on limited machines. Ok, not totally TCL compatible, and no TK, but you have (WIP) SDL2 bindings, and SDL2 would work perfectly on a display handled by fbdev/KMS. > but blending and other advanced 2…

EFL should never be recommended as a serious option.

Depends, maybe when the recommender is serious about being exploited. /s

Re: So you want to build an embedded Linux system? (2020)

#13

Post by blueflow »

foxfluff wrote: post #11
blueflow wrote: post #7

I have issues with the section "Microcontroller vs Microprocessor: Differences" Microprocessors are just the CPU, usually with the system bus wired out. Microcontrollers are combined systems, which include a processor and usually some kind of firmware storage and RAM. You can usually differentiate them by whether their pins are address/data lines or gpio-like. > microprocessors have a memory management unit The 8086…

It's a pointless distinction by and large. Microcontrollers may or may not have storage for firmware. Requiring an off-chip flash is nothing new. Microcontrollers have SRAM, but so do processors. That's where the firmware runs before it gets the DRAM running. Microcontrollers may include a bunch of peripherals, but so do processors. Especially so if you refer to SoCs as processors, like the article here does. And SoC…

The distinction used to be "Whether the bus is exposed externally".

> Microcontrollers have SRAM, but so do processors. That's where the firmware runs before it gets the DRAM running.

Which microprocessor architecture does this?

Re: So you want to build an embedded Linux system? (2020)

#14

Post by thrashh »

foxfluff wrote: post #11
blueflow wrote: post #7

I have issues with the section "Microcontroller vs Microprocessor: Differences" Microprocessors are just the CPU, usually with the system bus wired out. Microcontrollers are combined systems, which include a processor and usually some kind of firmware storage and RAM. You can usually differentiate them by whether their pins are address/data lines or gpio-like. > microprocessors have a memory management unit The 8086…

It's a pointless distinction by and large. Microcontrollers may or may not have storage for firmware. Requiring an off-chip flash is nothing new. Microcontrollers have SRAM, but so do processors. That's where the firmware runs before it gets the DRAM running. Microcontrollers may include a bunch of peripherals, but so do processors. Especially so if you refer to SoCs as processors, like the article here does. And SoC…

It’s such a blurry line now because with so many vendors, you can find everything on a spectrum these days

Re: So you want to build an embedded Linux system? (2020)

#15

Post by Terry_Roll »

blueflow wrote: post #7

I have issues with the section "Microcontroller vs Microprocessor: Differences" Microprocessors are just the CPU, usually with the system bus wired out. Microcontrollers are combined systems, which include a processor and usually some kind of firmware storage and RAM. You can usually differentiate them by whether their pins are address/data lines or gpio-like. > microprocessors have a memory management unit The 8086…

There is no global standard of definitions, what you might be seeing is the difference in the educational system in different parts of the world.

We know definitions change over time because slang words come and go and someone's vocabulary can be used to identify people online or identify their knowledge.

Re: So you want to build an embedded Linux system? (2020)

#16

Post by AlotOfReading »

blueflow wrote: post #13
foxfluff wrote: post #11

Earlier quoted context omitted.

It's a pointless distinction by and large. Microcontrollers may or may not have storage for firmware. Requiring an off-chip flash is nothing new. Microcontrollers have SRAM, but so do processors. That's where the firmware runs before it gets the DRAM running. Microcontrollers may include a bunch of peripherals, but so do processors. Especially so if you refer to SoCs as processors, like the article here does. And SoC…

The distinction used to be "Whether the bus is exposed externally". > Microcontrollers have SRAM, but so do processors. That's where the firmware runs before it gets the DRAM running. Which microprocessor architecture does this?

Most of them? Pretty much every ARM board supports an SRAM boot stage, for example. If you're using U-Boot, it's pretty likely that there's a SPL running out of SRAM somewhere in there.

Re: So you want to build an embedded Linux system? (2020)

#17

Post by blueflow »

AlotOfReading wrote: post #16
blueflow wrote: post #13

Earlier quoted context omitted.

The distinction used to be "Whether the bus is exposed externally". > Microcontrollers have SRAM, but so do processors. That's where the firmware runs before it gets the DRAM running. Which microprocessor architecture does this?

Most of them? Pretty much every ARM board supports an SRAM boot stage, for example. If you're using U-Boot, it's pretty likely that there's a SPL running out of SRAM somewhere in there.

ARM is a microcontroller architecture.

Re: So you want to build an embedded Linux system? (2020)

#18

Post by R0b0t1 »

blueflow wrote: post #17
AlotOfReading wrote: post #16

Earlier quoted context omitted.

Most of them? Pretty much every ARM board supports an SRAM boot stage, for example. If you're using U-Boot, it's pretty likely that there's a SPL running out of SRAM somewhere in there.

ARM is a microcontroller architecture.

These words are used interchangeably, you need to specify exactly. The main distinction is does it have a MMU or not.

Re: So you want to build an embedded Linux system? (2020)

#19

Post by blueflow »

R0b0t1 wrote: post #18
blueflow wrote: post #17

Earlier quoted context omitted.

ARM is a microcontroller architecture.

These words are used interchangeably, you need to specify exactly. The main distinction is does it have a MMU or not.

"VPN" evolved to mean proxying service, now people are denying that my tinc setup is a VPN.

"Emulation" evolved to mean virtual machine, now people are denying that wine or xterm are emulators.

"Operating System" evolved to require virtual memory and paging, now people are denying that MS-DOS was an operating system.

"Microprocessor" evolved to mean computing chips with MMU, im waiting for people to deny that the 8086 was an microprocessor because it does not have an MMU.

The infinite shitcycle of people improvising language instead of researching.

Re: So you want to build an embedded Linux system? (2020)

#20

Post by blueflow »

Terry_Roll wrote: post #15
blueflow wrote: post #7

I have issues with the section "Microcontroller vs Microprocessor: Differences" Microprocessors are just the CPU, usually with the system bus wired out. Microcontrollers are combined systems, which include a processor and usually some kind of firmware storage and RAM. You can usually differentiate them by whether their pins are address/data lines or gpio-like. > microprocessors have a memory management unit The 8086…

There is no global standard of definitions, what you might be seeing is the difference in the educational system in different parts of the world. We know definitions change over time because slang words come and go and someone's vocabulary can be used to identify people online or identify their knowledge.

Whatever, but if someone of the "Distinction Criteria is existence of MMU" crowd comes and claims the 8086 is not a microprocessor, because it doesn't have an MMU (which would be a logical conclusion from the article). i'll probably not be respectful.
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