Acorn Antiques: Benchmarking the PiTube Co-Processor

One of the more intriguing modern peripherals for the BBC Micro and BBC Master is the PiTubeDirect co-processor board. Using a Raspberry Pi Zero, a simple interface board, and some clever bare-metal programming on the Pi, I can emulate a number of second processors on the BBC Master for under £20.
Link to the PiTubeDirect wiki here: github.com/hog...
And there are a number of external (BBC Model B and Master) and external (Master only) interface boards available. I purchased mine from Retro Clinic (www.retroclinic...) on eBay.

[@ncot_tech]

I always liked the story of how the Acorn Archimedes was developed using the BBC Micro.

[@BreakIntoProgram]

Yes! I love the anecdote about how the lower power design of the ARM processor was almost accidental; they discovered that the power lines to the chip were not properly connected on the development board when they first successfully tested it. Feels a bit 'Circle of Life' using a Raspberry Pi as a BBC co-processor. www.theregister.com/Print/2012/05/03/unsung_heroes_of_tech_arm_creators_sophie_wilson_and_steve_furber/

[@stupossibleify]

The expansion capabilities (particular the software provision in ROM) of the Beeb Model B were light-years ahead of anything at the time, albeit at some considerable cost. The Tube has always fascinated me, and thanks for clarifying that despite the speed the bottleneck remains the post box method of passing data to/from the Beeb itself

[@BreakIntoProgram]

Same here - so couldn't wait to try this in my Beeb. The benchmark results were a bit of a surprise to me, to be honest. It was still a lot quicker than I anticipated.

[@robertbruce7686]

Shame the result was so S L O W 😂

[@Soruk42]

Just for the sheer hell of it, I ran Gordon's mandelbrot program in Matrix Brandy BASIC (SDL graphics build) on a Raspberry Pi 3B+ running Linux - it rendered in 0.15s, so it does show that even with ASCII output the Tube interface is really slowing it down, as a 1GHz ARM running a BASIC implementation in pure ARM assembly should run rings around an implementation written in C even though the host machine is running at 1.4GHz.

[@RetroMarkyRM]

There's a patched version of Elite that runs on the ARM with filled in polygons. Very impressive. Check it out!

[@BreakIntoProgram]

Oooh, going to have to look out for that.

[@TheUAoB]

Have you tried the fixed flicker-free versions of 6502SP Elite?

[@samcoupe4608KB]

nula?

[@donaldklopper]

Next step: FPGA co-pro at 1GHz.

[@samcoupe4608KB]

what happens if u use the HDMI output from pie?

[@BreakIntoProgram]

I don't know. The Wiki doesn't mention it. I suspect nothing, as the PiTubeDirect software is written bare-metal, so no OS, and no need to service the HDMI port. You do get debug information if you connect a serial port to it.

[@samcoupe4608KB]

@@BreakIntoProgram do u know anything about the pie gpu?

[@Soruk42]

Nothing formally released as far as I know, but Dave (hoglet) is working on something in that regard.

[@samcoupe4608KB]

56mhz80 needs more video ram only 32kb no next support