Search found 1070 matches

by fordp
Thu Dec 03, 2015 7:18 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Another thing I have noticed with the Pi is there are quite large gaps between the bytes, which at the moment is the limiting factor. Is this also the case with your bare-metal SPI implementation? Dave I read about the gaps on the Pi Forum and they are deliberate and part of the Hardware. They are ...
by fordp
Thu Dec 03, 2015 7:02 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

I have my .gdbinit script working-ish now . I upped the the speed and a bit is taking 70ns or so now or 28.5 MHz :D I am not totally sure as my logic analyser only runs at 100MHz :wink: It looks consistent and not at all lumpy. This is using Polling and I think with the Raspberry Pi's cache is switc...
by fordp
Thu Dec 03, 2015 6:21 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Hi Dave, Thanks for the latest update. The work around of the extra byte is fine for now but my gut feeling is that with a change of the HDL it should not be needed. With your simple wrapper and maybe the OpenCores SPI I wonder how efficient it all is. We do not need an generic SPI module and a stri...
by fordp
Thu Dec 03, 2015 6:58 am
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

One more closing thought.... In your original SPI protocol, you included multi-byte writes (and reads?). Do you still think this makes sense? Given most of the FIFOs in the Tube "chip" are just one-byte deep, the client code needs to check for space before sending each byte, which involves polling ...
by fordp
Thu Dec 03, 2015 1:35 am
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

I would have done more but my Daughter broke her wrist and I had to go and fetch her. 3 hours driving and many hours waiting in A&E. Hi hum.

FordP
by fordp
Wed Dec 02, 2015 8:03 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Risk.jpg
I have reworked the driver.

Push to Github.

More tomorrow.
FordP
by fordp
Wed Dec 02, 2015 3:22 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Amazing job Dave. The project will be one week old tomorrow :D

FordP
by fordp
Wed Dec 02, 2015 10:45 am
Forum: 8-bit acorn hardware
Topic: Beeb FPGA
Replies: 513
Views: 49757

Re: Beeb FPGA

If you are talking hardware :
http://www.digikey.co.uk/product-search ... ageSize=25

:D

FordP
by fordp
Wed Dec 02, 2015 8:16 am
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Well done Dave,

One step closer with the "Tube Chip" now in the DE1 Build :D

FordP
by fordp
Wed Dec 02, 2015 8:03 am
Forum: 8-bit acorn hardware
Topic: Beeb FPGA
Replies: 513
Views: 49757

Re: Beeb FPGA

I know this is a toughie but is surely the icing on the cake, Saveable CMOS settings, whether you can utilise a cmos.bin file on the SD card or use some bytes in the flash ram.. but it would really be the ultimate BBC Master FPGA system. Amazing work, I salute you sir :) Two ways to make this happe...
by fordp
Tue Dec 01, 2015 11:46 pm
Forum: 8-bit acorn hardware
Topic: Beeb FPGA
Replies: 513
Views: 49757

Re: Beeb FPGA

Wow amazing progress. This is all without using the SDRAM. I originally sent Zeus a DE1 to get his project in to the main stream. He then worked wonders and ported his project to the the DE0 which did not have any SRAM. This should mean that the 80186 Second Processor can run in the SDRAM while the ...
by fordp
Tue Dec 01, 2015 7:25 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Not much time for hacking as I am going out and I have just installed my new pair of Black Friday bargains a matching pair of 4K Screens :D I have my PC all set up and board running again. I found a better SPI resource the real SPI Driver https://github.com/notro/spi-bcm2708 ! It is way more complex...
by fordp
Mon Nov 30, 2015 11:41 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Would this work on a Pi Model B? I have a couple of these... One other thing I've been thinking of is latency....During the tube data transfers, the host does not use any kind of flow control, and so the parasite must be able to source/sink data sufficiently quickly, otherwise data corruption occur...
by fordp
Mon Nov 30, 2015 10:05 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

The next step is to get the Pi hooked up to tube interface. I do not have a Matchbox LX9 and even if I did I do not think I have the skills to add an SPI interface to the Tube HDL. I was thinking a possible way forward is to add the Tube HDL to the BeebFPGA project on the DE1? The existing parallel ...
by fordp
Mon Nov 30, 2015 9:29 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Thanks for the heads up. There are many options for GDB front-ends and I am sure much pain until I get something I am happy with. A set-up tutorials to save me stumbling in to the inevitable gotchas? EDIT: I am trying the DARK side that is Eclipse CDT. I need something to challenge my AMD 4GHz 8 cor...
by fordp
Mon Nov 30, 2015 9:12 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

GDB Remote dubugging

A bit more progress this evening. I managed to build and write a GDB Stub from GitHub to an SD Card and connect to it using GDB from the command line and send last nights program over the serial connection and run it. I have had a go at documenting what I did here: https://github.com/fordp2002/ArmCo...
by fordp
Mon Nov 30, 2015 6:48 pm
Forum: 8-bit acorn hardware
Topic: Electron FPGA
Replies: 114
Views: 12609

Re: Electron FPGA

I built it in Quartus and it works!
14489092193611557594102.jpg
I still do not know how to use an Electron, and my BBC music programs will not work I presume!

Edit: Just checked and the Beeb still works so I must have done something right!

Cheers
FordP
by fordp
Mon Nov 30, 2015 2:22 pm
Forum: for sale / freebies
Topic: Worth Taking a Look At
Replies: 2841
Views: 305312

DE1 Board

The are much cheaper to buy from Digikey the last time I looked.

Cheers.

FordP
by fordp
Sun Nov 29, 2015 11:20 pm
Forum: 8-bit acorn hardware
Topic: Electron FPGA
Replies: 114
Views: 12609

Re: Electron FPGA

Hi Dave,

I will give it a go on Monday night and report back.

I have never used and Electron!

Cheers.

FordP
by fordp
Sun Nov 29, 2015 8:57 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

I have smartened up and posted the first code here:
https://github.com/fordp2002/ArmCopro

Note: This is just a bare metal SPI demo from the web at the moment and a start on the Wiki.

FordP
by fordp
Sun Nov 29, 2015 6:34 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Well that is a lot of hours I am not going to get back ;)
spi.jpg
But I have a Bare Metal SPI signal coming ot of a Raspberry Pi,

I will write up the useful bits of my findings and make a Github Repositary in due course.

In the meantime it is tea time!

FordP
by fordp
Sat Nov 28, 2015 11:10 pm
Forum: 8-bit acorn hardware
Topic: P.R.E.S. New and Original AP6 - All sold! New batch in development
Replies: 151
Views: 18409

Re: P.R.E.S. New and Original AP6

Rather than adding support for battery backed RAM would adding support for 32K FRAMs be a better option? Batteries have killed so many products. I have not tried them but they look like they would work. Ford P Err, what battery backed RAM? The New AP6 does not have any battery! Mark I was referring...
by fordp
Sat Nov 28, 2015 7:28 pm
Forum: 8-bit acorn hardware
Topic: P.R.E.S. New and Original AP6 - All sold! New batch in development
Replies: 151
Views: 18409

Re: P.R.E.S. New and Original AP6

Rather than adding support for battery backed RAM would adding support for 32K FRAMs be a better option? Batteries have killed so many products. I have not tried them but they look like they would work.

Ford P
by fordp
Sat Nov 28, 2015 6:00 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

I guess the Broadcom SoC in the Raspberry Pi has been substantially investigated, but the opaque boot payload and other closed aspects of the design probably made such investigation a fair amount of work that really should have been avoided. Allwinner stuff also suffers from manufacturer misbehavio...
by fordp
Sat Nov 28, 2015 11:05 am
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

An excellent webpage on bare metal on the pi here: http://www.valvers.com/open-software/raspberry-pi/step01-bare-metal-programming-in-cpt1/ I personally like to write at the C level. I get by debugging at the assembler level but like to code using C as I make too many mistakes doing assembler. We ar...
by fordp
Sat Nov 28, 2015 10:38 am
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Here possibly some useful links for building code for the Pi: Compiler: http://stackoverflow.com/questions/19162072/installing-raspberry-pi-cross-compiler Note it maybe be easier on Linux? The question refers to Ubuntu, but perhaps you mean that it might be easier on another GNU/Linux distribution....
by fordp
Fri Nov 27, 2015 10:18 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Here possibly some useful links for building code for the Pi: Compiler: http://stackoverflow.com/questions/19162072/installing-raspberry-pi-cross-compiler Bare Metal Example on GitHub: https://github.com/brianwiddas/pi-baremetal/ I will try and get this example going in the first instance! Very simp...
by fordp
Fri Nov 27, 2015 9:56 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Would this work on any Pi with GPIO? Indeed Jon, This could easily be made to work on any Raspberry Pi, I am thinking of using the Zero as the main target due to it's low cost and small size. I think 512MB of RAM is plenty for a second processor! Most of the Pi's use the same ARM11 Soc with more or...
by fordp
Fri Nov 27, 2015 8:59 pm
Forum: 8-bit acorn hardware
Topic: Raspberry Pi Zero as a Second Processor anyone?
Replies: 988
Views: 81708

Re: Raspberry Pi Zero as a Second Processor anyone?

Indeed the LEDs may be the easiest option. The RAM pins could be used easily too if there is no RAM as there are vias on all the address pins and if they do not have solder mask in the vias they are easy to solder. Looking at the PCB there may be plenty of spare pin on the FPGA as we only need 6. St...

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