On a sunny day (Sun, 31 May 2020 08:40:11 -0000 (UTC)) it happened Martin
Gregorie  wrote in :

>On Sun, 31 May 2020 07:47:34 +0000, Jan Panteltje wrote:
>
>> Kids try programing some Microchip PIC chips if you want to learn how to
>> control things, those are 2 1/2 $ upwards.
>> Learn some basic electronics.
>>
>Makes sense.
>
>Some years back I did something similar with the Parallax Basic STAMP,
>a tiny SMD board that fit a 24 pin chip socket. Worked well, and had a
>very good IDE for programming and debugging, an decent integer BASIC (if
>that's not a complete oxymoron) but wasn't cheap.

Ah yes.


>Its still around, but largely replaced by the PICAXE chips, which are
>really cheap-as (all PICAXE chips cost less than 10 Euros) and range in
>size from 8pin DIP chips to (IIRC) 40 pin DIP packages. They all contain
>a Pic MPU, RAM and EEPROM anf accept binary uploads over a serill port,
>so the compile/load/test cycle is fast and easy to manage. They are
>designed to be programmed in a somewhat crap integer BASIC. You use your
>favourite editor to write programs and an decent compiler/loader to sling
>the result into the PICAXE chip. The chip contains a lot of built-in
>stuff, such as servo drivers, A->D and D->A converters that are really
>useful for real-world applications.
>
>For really small projects. e.g. robots or small model aircraft where the
>controller must weigh under 10g, fit in a 1cm cube, etc, the PICAXE is
>the way to go.

I build a 8052 BASIC chip, in the eighties, it is still working :-)

http://panteltje.com/pub/8052AH_BASIC_computer/8052AH_BASIC_computer_inside_img
_1727.jpg
it could also program EPROMs.

For light weight projects PICs:
 http://panteltje.com/panteltje/quadcopter/index.html
  and low power consumption!
        AND real time
    AND zero boot time (very important here)

And all that in a few kB FLASH and 256 bytes of ram and 32 bit math
Remember the original Apollo missions to the moon and back used a flight
computer that was less
powerful than a Raspi 1

Where does it go?
Most of the media encoding / decoding (mpeg etc) is done in custom hardware
these days.
One could think (I did) just like in the seventies when audio amps with 0.0001
% distortion
were considered much better than the ones with 0.001 %, now it is GB RAM used
as sales argument.
Same you see with the number of pixels in smartphone cameras.
They should start with the lenses, the lenses in those cameras are so shit that
my Canon with good lenses
and less than a quarter of the pixels gives better detail...
But those phones need to be flat...




I program PICs (18F14K22 these days) in asm.
Contrary to what some may believe it is easier than C.

But there is an other reason I use PICs in combination with 'puters
that is because Linux is by origin a multi-tasker.
That means, that unless you have some access to system interrupts,
your data transfer will be interrupted on a regular basis by the OS
task-switch.
To prevent streaming problems you then need an external buffer.
A PIC and other hardware connected to for example GPIO can then do the
real-time part,
buffer the data when the Linux OS on the Raspi is task switching... FIFO
buffer:
 http://panteltje.com/panteltje/raspberry_pi_dvb-s_transmitter/

In the same way using the USB as interface is than possible.
As the cheap PICs also have ADCs and many I/O pins, you basically
add analog an digital I/O.
Using a simple USB to serial adaptor allows the cheapest PICs to do the time
critical parts:
 http://panteltje.com/panteltje/pic/col_pic/
 http://panteltje.com/panteltje/pic/ir_pic/



>I'n not knocking the RPi, just pointing out that, as what is a
>effectively a vastly shrunken and cheaper desktop device running a proper
>OS (regardless of whether you're a Debian fan or not) there are projects
>where something like a ParallaX STAMP or a PICAXE is the better solution.
>
>> How many fucking variables has the biggest program you ever wrote ???
>> Any idea how much 8 GB is?
>> 8,000,000,000
>>
>Lots, if you include database systems doing complex tasks, such as
>managing the creation, production, contractual details and broadcasting
>of classical concerts and other related programs, but I agree about the
>8GB - we did that in 16MB for multiple users *but* that was on a
>mainframe with greenscreen 80x24 terminals so no memory wasted pissing
>about with fancy graphical displays or hifi binaural audio streams. Those
>are what chews up the memory in modern desktop systems and phones.

Yep, I have an old Duron 950 MHz Linux PC running, it has 2 sound cards, 1
satellite
card, and about 500 MB memory. 3 harddisks, DVD burner...
now about 16 years old, never ever had a resource problem, it runs grml (also a
Debian based system),
still use it every day.. recompiled kernel a couple of times..
It also has a parport, great for I/O things like testing i2c and SPI busses as
those are not sensitive
to tasks witch interrupts.

As media player .. I watched the SpaceX launch yesterday with Chromium on my
4GB Pi4...

But then again, my 24$ made in China DVB-T2 terrestrial sat box also has a RJ45
connector and a youtube menu option,
and can play HD youtube videos. I think it runs Linux....

The market for media players / phones is a very big one and prices are way down
because of competition.

Did so many PIC projects:
 http://panteltje.com/panteltje/pic/index.html

Other open source stuff:
 http://panteltje.com/panteltje/newsflex/download.html


And then there is FPGA, make your own processor and hardware software
configurated on a chip.

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