£3.60

Hmm, not a real Pi in any sort of way at all, it's a microcontroller with no OS. It's only a Pi because it's made by the same company.

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Chris Green

Dana Thu, 21 Jan 2021 15:49:58 +0000, Andy Burns napis'o:

But... it should not be called pi. People will whink it is like zero... but smaller. They should've named it something different.

Agreed.

However, I've still bought one to experiment with because, unlike PICAXE chips, I can program it in C, its already mounted on a small PCB and it is slightly cheaper than the equivalent PICAXE I need for my project.

Like the PICAXE, it can also do the things I need without any extra circuitry, such as detecting whether a switch is on or off, direct control of servos and of speed controllers for brushless electric motors (via its PWM outputs).

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Martin    | martin at 
Gregorie  | gregorie dot org

... and it's a great disappointment to me that it's not a 64-bit processor

Raspberry Pasty?

... should have read 'only around twice the price of the PICAXE M14'

From a first look at the docs, its somewhat better documented, too.

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Martin    | martin at 
Gregorie  | gregorie dot org

Looks like it aims to be an Arduino competitor, so yeah, it's a computer, but not in the same "runs a desktop" sense as the others in the "Pi" lineage.

Elijah

------ it even looks like an Arduino

Name one.

:-)

(assuming you meant it as a joke)

As the Pi4 is a 64 bit processor, one assumed that all future developments by that company would be 64 bit.

Why? I see no reason for such an IOT device to need more than 32 bits at the outside: it has no embedded OS, is not multi-tasking and doesn't need to be, so the only good reason to have more than 16 bits of address space is to accommodate the size of modern support libraries - after all its designed to allow current C and C++ libraries to be used, and lacking any i/o devices faster than USB, its unlikely to be processing large data volumes.

I'd say that reducing its power consumption is more important: its quiescent state uses around 10 mW - a bit more than some battery driven applications where quiescent periods are much longer than bursts of activity might be comfortable with.

It looks interesting to play with anyway, and I'll certainly be interested to see how using its FSMs can be used and how they affect code size.

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Martin    | martin at 
Gregorie  | gregorie dot org

That's a general purpose CPU for use in general purpose computers (like the Pi 4). This new thing is a microcontroller chip for use in microcontrollers. There are currently no 64-bit microcontrollers on the market. I can imagine it one day moving that way, maybe for portable image recognition stuff? For now, it would be a very, very specialised niche and that's not Raspberry Pi's aim.

Indeed. I've yet to find a need for more than eight bits in a microcontroller, along with a maximum of 2KB of RAM. If I need more power, it's a RPi.

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Joe

I don't really get the market positioning of this. 'Arduino' is these days a programming interface, which runs on a variety of platforms from the original 8-bit ATMega to the x86 Intel Quark and MIPS chips running Linux. Users have been gradually moving from ATMega to ARM-based microcontrollers like the STM32 on boards like the Blue Pill.

The Blue Pill doesn't have first party Arduino support, but the part is widely available for cheap. The RP2040 has slightly better specs, but there's a whole range of STM32s to choose from if you're willing to pay slightly more. The STM32 is also widely available for production from the usual distributors, while it remains to be seen whether you can buy the RP2040 in production volumes from distributors, or whether you have to do something 'special' (ie painful and awkward for a manufacturer).

Also the 'teaching' market for microcontrollers is a bit crowded, with all the Arduinos, the BBC Micro:bit, as well as all the vendor platforms.

I can see the wish to own the ecosystem, as they do by being single-supplier of the Pi SoC. Maybe the software ecosystem will develop around this like it has around Arduino, such that it's a no-brainer to use in a project because of the high quality libraries and documentation available. But hardware-wise there's nothing particularly earthshattering here.

Theo

It is 50 years ago this year that I cut my teeth on a naked PDP11/20 with no OS and only an assembler. Everything I did was up to me.

Over the years I have been involved in real-time OS development and language interpreters to the extent that in my retirement I've an N-I-H stance towards others' software.

I'd like to relive my youth but with the 64-bit instruction set of the ARM but without being imbrangled in all the bolt-on (Lancashire? :-) ) goodies that the RPi4 has.

I don't have the capability to produce the PCB and solder down a BGA myself, despite a radio ham's junk box of nearly 60 years' standing.

In my retirement, I have some ideas on language development, essentially interactive as was BASIC and FORTH but running at the speed of compiled code, and the 64 bit ARM instruction set looks like a good starter.

FORTH was good stuff speed wise

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Climate Change: Socialism wearing a lab coat.

Ah, but the normal process would be to enter the boot loader by hand, then a bigger/better loader from paper tape and then the actual OS.

Or did you actually write naked assembler code to do things direct with the hardware?

I started at a similar time (early 1970s) on a wierd device called the PDP-12 (an odd marriage of a PDP-8 and a university developed machine called a Linc-12).

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Chris Green

I never used it in anger, but spent a lot of time thinking about it. I seem to have on my bookshelf most of the FORTH and TIL primers. I was considering something like a FORTH but not being based upon Reverse Polish.

ISTR that FORTH on an RCA 1802 is in the Voyager missions?

Now, that was a weird instruction set! ISTR 8-off 16 bit registers but no 16-bit moves, all having to be done in

8-bit chunks through the accumulator, and no conventional subroutine call but change which of the 16-bit registers at any time was the program counter!

Op 22-01-2021 om 14:22 schreef gareth evans:

A Teensy 4.x might be a good start. ARM Cortex M7 600 MHz, floating point hardware, lots of RAM and flash.

(It says 64-bit fp...! :) but I think that's "just" an accelerated simulation using 32-bit register pairs.)