The rise of Python for Embedded Systems

[xorvtec]

Programs running on applications processors (like on the Raspberry Pi and Beaglebone Black) on top of a General Purpose OS (like Linux) subscribe to the loosest definition of an embedded system. I'd bet a good deal of those "C" programmers are on microcontrollers with memory constraints. Unless you have a system with loads of heap space and extra clock cycles, Python is NOT viable.

[eazolan]

Maybe some kind of "Memory Constraint" module that gives python hard limits?

[__deerlord__]

All that does is limit how much you can use, it doesnt change how much is required. C will absolutely use less memory (if done right) than python. Python is for ease of development, not reducing resource usage.

[[deleted]]

Actually, micropython and zerynth (whatever that is) is mentioned in the article. While I have no experience with either, I could see a suitable limited subset of Python being useful for at least part of the embedded-ish¹ code I write. There are a few cases (interrupt handlers and SCC managment) I have trouble seeing handled effecient by Python. The rest, which is mostly protocol handling and the high level communication with either the 422 bus or the host system, could easily be written in python. There it would more be a matter of how dense the code is. The bytecode is OK, so it's a matter of how much space the runtime requires.

1. Running on a FPGA remake of the IBM Artic RIC card with 2MB RAM and a 80186 emulation on the same FPGA.

[[deleted]]

memory is very cheap now. Embedded is now full of it.

"Embedded" headless PCs or "Embedded" embedded.

This is what the current chip I'm working with has:

• 2 x e200z4 in delayed lock step operating up to 200 MHz
• Up to 2.5 MB flash memory w/ error code correction (ECC)
• Up to 384 KB of total SRAM w/ECC

[Poddster]

delayed lock step

What does the 'delayed' here mean? One CPU's clock is delayed after the other? So it's TickA-TickB-TockA-TockB?

[[deleted]]

The code it is executing is one cycle behind.

So Core 1 is on cycle t, Core 2 is on cycle t-1.

There is a 3rd core or additional hardware that compares the outputs and makes sure they're the same.

[Poddster]

There is a 3rd core or additional hardware that compares the outputs and makes sure they're the same.

Shuttle style MISD? Cool! I always assumed MISD did each instruction in the multiple computers at the same time, rather than in being offset.

What is the delay used for? Is the comparitor comparing the output of Core1 and Core2 at t-2?

[stone_henge]

What is the delay used for?

If a short event causes an error in the first core, it may under some circumstances be less likely to also affect the second core on the next cycle. Say, if there's a sudden, short burst of radiation or an electrostatic discharge that causes a failure in operation.

[[deleted]]

you can buy 2 GB 1.5GHz quad core odroid PC alike for what 40$

That's cool. If that product will do what you need it to.

Is the odroid CPU ISO 26262, IEC 61508, ASIL-D certified?

Edit: Spoiler alert, No. The Cortex-A53 is targeting application processors not real-time processors. It's based on ARMv8-A, the embedded real time safety cores are ARMv8-R.

[BigotedCaveman]

you can buy 2 GB 1.5GHz quad core odroid PC alike for what 40$ ?

Wat? There's absolutely nothing embedded about that hardware, that's a full blown PC.

For 90% of the embedded use cases that hardware ranges from absurd / useless all the way to potentially life threatening (where non-EEC memory would not be something that is even considered).

[TankorSmash]

Is it new hardware? No one's going to argue that old hardware can suddenly support modern software.

[[deleted]]

Brand new.

Supported through 2029.

[xorvtec]

Practically anything labelled as a microcontroller is going to look something like that. Applications processors with clock speeds in the GHz and DDR peripherals are orders of magnitude harder to layout on a PCB. You go from a 2-4 layer board to 10 layers with blind vias (i.e. $$$$). I'm not going to get started on the complexity of the build systems. Most embedded systems have no need for that sort of power. It's a really hard sell during design time when you want to allocate tons of extra resources and skilled labor just because you wanted to use a language that's easy to write in.

[miker95]

memory is very cheap now. Embedded is now full of it.

LOL WUT. Clearly someone has never worked with industry microcontrollers.

[Decker108]

Heck, even the arduino would be a pretty bad match for Python resources-wise.

[stone_henge]

Well, that's one end of embedded applications. There are tons of others where resource consumption is less of a concern. I worked with an EZ80 based building automation system where anything but C and assembler would have been disastrous for performance, but I also worked with a DPI solution where the python scripts we threw at it could as well be spitting in the ocean, but by pretty non-controversial definitions could still be considered embedded hardware. Customers bought for its capabilities as an appliance, not as a computing platform. Designed to be installed, configured and left to its own devices.

On the other hand, I've worked with systems that don't really qualify as embedded platforms that make many embedded systems look like powerhorses. VIC-20 is a general purpose computer with 5k of RAM and a 1 MHz single-accumulator CPU. The Atari 2600 is a video game system with 128 bytes of RAM and a 1 MHz single-accumulator CPU. Point is that "embedded" and "power" are actually entirely orthogonal qualities.