Re: [Emc-users] Has anyone played around with this: Pi-paraport

2018-08-11 Thread andy pugh 
On 10 August 2018 at 01:30, Greg Bentzinger via Emc-users
 wrote:
> Has anyone played around with this: Pi-paraport

I made some of these, and gave them away at the Wichita fest:
https://photos.app.goo.gl/vi8GJQZfBKV94jnH8

I am currently trying to get the Machinekit Pi GPIO driver to compile
on LinuxCNC. (many years later, and for unrelated reasons)

LinuxCNC would not need or want the p-port described in the link.

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Re: [Emc-users] Has anyone played around with this: Pi-paraport

2018-08-10 Thread Gene Heskett 
On Thursday 09 August 2018 22:02:01 Mark Johnsen wrote:

> > The parport emulator is available, but why tie up 90% of the gpio,
> > when it can be done faster with just 4 wires?
>
> You have a point, but there's probably more paraport BOB's available
> than the 4 wires spi boards.  Probably less $$ for a simple paraport
> BOB.
>
> But, I do like the SPI 4 wire solution, is pretty slick.
>
> Mark

Note that I am usually referring to the gpio available from the likes of 
a mesa 7i90HD interface card, not the 4 that are used to implement the 
spi on the pi itself.

The 7i90HD is about $70, and gives you up to 72 gpio's. But its a fpga, 
and can be destroyed by motor switcher noises and such that exceed 3.4 
volts. Its output is on 50 pin scsi like connectors, which aren't the 
handiest way to connect it to the real world, so there is also the 
7i42TA, a bit over $40/copy, designed to protect the 7i90 from that sort 
of destructive noise, and gives you a couple rows of the green screw 
terminal strips to plug your wires to the real world into, and you then 
need only to make up the short 50 pin cables to jumper from the 7i90HD 
to the 7i42TA's. My 26 wire cable from the pi to the 7i90 is maybe 1.5" 
long, achieved by turning the pi upside down, removing the 180 degree 
twist in the cable at the same time. The 50 pin cables are 3 to 6" long 
and I have the 7i42TA'S stair-step stacked on top of the 7i90HD. The 
write speed of a 32 bit packet from the pi to the 7i90HD is 42 megabaud, 
and the data coming back is read at 25 megabaud. So I think that rather 
handily beats the parports speed while using only 3 pins and grounds on 
the pi's long connector. Doing a parport right on the pi will use just 
about every gpio it has.

Firmware for the 7i90HD can be run from a parport, or the spi, you just 
have to program it with the right *.BIT file. I keep an old slow Dell 
around just to program mesa cards with mesaflash. It doesn't run on 
arm's (yet).
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Re: [Emc-users] Has anyone played around with this: Pi-paraport

2018-08-09 Thread Gene Heskett 
On Thursday 09 August 2018 20:30:19 Greg Bentzinger via Emc-users wrote:

> Has anyone played around with this: Pi-paraport
>
> https://github.com/garlick/pi-parport
>
>
I think on the pi-3b, spi is likely faster than a parport. Thats how I'm 
running a Sheldon Lathe 
>
> I had been wondering if a paraport emulator or an SSerial adapter
> could be made for the Pi GPIO
>
The parport emulator is available, but why tie up 90% of the gpio, when 
it can be done faster with just 4 wires?

> The new question is can it be shoehorned into a realtime environment.
>
On the pi-3b? Absolutely.

> I was thinking a ODroid XU4 imaged with DietPi and building upwards
> from that foundation.

That might require the parport. rpspi.ko ONLY runs on a pi-3b. From the 
rpspi.ko to a mesa 7i90 with 3 7i42TA's gives you more stuff and gpio's 
than is needed, 72 pgio's total. I've got gpio using gingerbread in my 
hal file and gui's and still have 15 or more gpio's unused. And the pi 
is still loafing.

> Worst case I use a genuine Pi 3 with the flash update to boot from
> external HDD (no more SDcard drama)
>
> What say the hive mind?
>
> Greg
>
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 soap, ballot, jury, and ammo. Please use in that order."
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Genes Web page 

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Re: [Emc-users] Has anyone played around with this: Pi-paraport

2018-08-09 Thread Chris Albertson 
What to boot off a hard drive?  Try "TFTP".   The hard drive is physically
connected to some other computer on your network and the Pi uses the
network to access it.   TSTP is the boot protocol used.

At one place I used to work the IT department set up user desktop PCs to
use TFTP to book a standard disk image from a server.  The desktop PCs did
not have ANY local storage.   Why?  Because if there is zero local storage
there is nothing to configure and nothing to loose if it crashes and zero
chance of a virus.If the machine fails the TI guy simply un-boxes a
brand new machine and puts in on the desk and powers it up.  that's it.
The broken computer fits in the box and gets shipped back to the vendor.
ZERO configuration means zero problem solving.

The other thing it meant is that EVERY computer in the company can be used
by any employee and his desktop and files follow him

You can run a Pi3 the same way.

On Thu, Aug 9, 2018 at 5:31 PM Greg Bentzinger via Emc-users <
emc-users@lists.sourceforge.net> wrote:

> Has anyone played around with this: Pi-paraport
>
> https://github.com/garlick/pi-parport
>
>
>
> I had been wondering if a paraport emulator or an SSerial adapter could be
> made for the Pi GPIO
>
> The new question is can it be shoehorned into a realtime environment.
>
> I was thinking a ODroid XU4 imaged with DietPi and building upwards from
> that foundation.
>
> Worst case I use a genuine Pi 3 with the flash update to boot from
> external HDD (no more SDcard drama)
>
> What say the hive mind?
>
> Greg
>
>
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