Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

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dp11
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by dp11 » Fri May 18, 2018 5:06 am

Pi3b+ is much faster.

Timings from memory for fast 6502

Pi2 slower than pizero
Pizero 290MHz
Pi3 290MHz
Pi3B+ 336MHz

I have some more speed increases in the pipeline that take the 3b+ to 340MHz.

The original acorn external 6502 copro was 3MHz so 3b+ is over 110 times faster.

Other cores see a speed increase with the 3b+ too.

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Elminster
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by Elminster » Fri May 18, 2018 8:38 am

Great thanks. Perhaps I need another Pi 3B+ then. Trouble is I already have 15 RPIs. Perhaps I shall have to have a clear out soon!

dp11
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by dp11 » Fri May 18, 2018 5:35 pm

Just tried running CLOCKSP on native ARM and rpi3b+. Unfortunately it is too fast and gives a divide by zero error as the time for the floating point test <10mS . I guess the speed result to be around 19-20GHz as bas135 floating point is much faster than BASIC II on a beeb.

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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by northernbob » Sun May 20, 2018 2:25 pm

dp11 wrote:Pi3b+ is much faster.

Timings from memory for fast 6502

Pi3 290MHz
Pi3B+ 336MHz

I have some more speed increases in the pipeline that take the 3b+ to 340MHz.

.
i realise this is getting a bit silly, but have you tried overclocking the 3b+ ? or does this just mess things up?

https://youtu.be/RxBaEiQHzLU

guide to overclocking the beast.....1.6ghz max
https://youtu.be/aT0OX8TXRCM

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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by sundbyk » Sat May 26, 2018 12:01 pm

dp11 wrote:
Fri May 18, 2018 5:06 am
Pi3b+ is much faster.

Timings from memory for fast 6502

Pi2 slower than pizero
Pizero 290MHz
Pi3 290MHz
Pi3B+ 336MHz

I have some more speed increases in the pipeline that take the 3b+ to 340MHz.

The original acorn external 6502 copro was 3MHz so 3b+ is over 110 times faster.

Other cores see a speed increase with the 3b+ too.
Hi,

Which version of the Pi Zero are you testing on?
My Pi Zero V1.3 report 417Mhz in Combined Average.

Kjell S.
***************************
Kjell Sundby
Web: http://www.sundby.com
****************************

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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by dp11 » Sat May 26, 2018 12:46 pm

I suspect you are using basic IV e.g. A master. To be consistent we using Basic II for all the timinigs.

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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by sundbyk » Sat May 26, 2018 1:34 pm

dp11 wrote:
Sat May 26, 2018 12:46 pm
I suspect you are using basic IV e.g. A master. To be consistent we using Basic II for all the timinigs.
Hi,

Your are right.
I did use the Master version.
Thanks for clearing that up for me.
:-)

Kjell S.
***************************
Kjell Sundby
Web: http://www.sundby.com
****************************

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marcusjambler
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by marcusjambler » Tue May 29, 2018 8:01 am

I think there maybe an issue with running the 286 processor on a PI Zero.
I have it booting fine to DOS from BeebSCSI.
If I catalogue a disk that has a large no of files in a sub_directory on GOTEK using DIR it hangs randomly during that process.
If I swap the PI Zero for a PI 3, no issue. ( Using the same SD card and image )

Marcus

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hoglet
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by hoglet » Tue May 29, 2018 8:58 am

Marcus,

Is there any way we could get a copy of the hard disk image that provokes this problem?

Dave

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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by marcusjambler » Tue May 29, 2018 9:06 am

Hi Dave

Its one I got from RobC but the standard Data Centre image also does it.
I'll post a 720k DOS disk image for 'Treasure Island' when I get home.
All the files are in 'Treas' sub-directory because of the Root directory limit ( IIRC 77 files max )

Marcus

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hoglet
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by hoglet » Tue May 29, 2018 9:19 am

marcusjambler wrote:
Tue May 29, 2018 8:01 am
I have it booting fine to DOS from BeebSCSI.
If I catalogue a disk that has a large no of files in a sub_directory on GOTEK using DIR it hangs randomly during that process.
I'm just trying to get my head around this configuration.

Is this all correct?
- You are running on a Master 128
- You are using the standard ADFS 1.50, with other file systems (DFS and RAMFS) unplugged
- The C:/ drive is implemented with BeebSCSI and is using RobC's hard disc image
- The A:/ drive is implemented with a GOTEK and you are using the "Treasure Island" 720K DOS image.

Ir's doing a DIR A:/ on a image with a lot of files that is causing a random hang on the Pi Zero, but not the Pi 3.

What release of PiTubeDirect are you running?

I don't have a GOTEK myself (yet...) but if someone could bring one along to ABUG this weekend I can look into this.

Dave

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marcusjambler
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by marcusjambler » Tue May 29, 2018 9:26 am

Is this all correct?
- You are running on a Master 128
yes
- You are using the standard ADFS 1.50, with other file systems (DFS and RAMFS) unplugged
yes although the issue arises under MOS 3.2 and 3.5
- The C:/ drive is implemented with BeebSCSI and is using RobC's hard disc image
Yes
- The A:/ drive is implemented with a GOTEK and you are using the "Treasure Island" 720K DOS image
Yes - using Up to date FlashFloppy release.

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marcusjambler
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by marcusjambler » Tue May 29, 2018 9:32 am

What release of PiTubeDirect are you running?
Egg Eater RC0 although Diamond Back does this as well.

I've had this situation pop up for a while and I convinced my self it was a cabling issue.
And I had it come and go whilst swapping peripherals from my Beeb SCSI master to my Retro Clinic Master.
But behind all the swapping was one fundamental difference.
The Beeb SCSI master has an internal level shifter with a PI zero mounted whereas the Retroclinic one has an External level shifter with PI 3 hung off it.

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hoglet
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by hoglet » Tue May 29, 2018 9:42 am

marcusjambler wrote:
Tue May 29, 2018 9:32 am
The Beeb SCSI master has an internal level shifter with a PI zero mounted whereas the Retroclinic one has an External level shifter with PI 3 hung off it.
Is the internal level shifter one of Kjell's new batch (i.e. bought or swapped out since Feb 2018).

Would it be possible to try the Pi Zero on the external level shifter in the BeebSCSI master?

Dave
Last edited by hoglet on Tue May 29, 2018 9:43 am, edited 1 time in total.

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BigEd
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by BigEd » Tue May 29, 2018 9:42 am

Is the Pi in both cases powered by the Beeb?

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marcusjambler
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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by marcusjambler » Tue May 29, 2018 9:47 am

Is the internal level shifter one of Kjell's new batch (i.e. bought or swapped out since Feb 2018).
Yes Kjell very kindly sent me a new one.
Would it be possible to try the Pi Zero on the external level shifter in the BeebSCSI master?
Yes I'll do that and post the result
Is the Pi in both cases powered by the Beeb?
Yes both Beeb powered.

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Re: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)

Post by marcusjambler » Tue May 29, 2018 4:09 pm

Would it be possible to try the Pi Zero on the external level shifter in the BeebSCSI master?
Of course... The PI Zero is working fine now on both internal and external level shifters :shock: :roll:

I'll monitor it and try and pin the cause down.

Here's the Treasure Island image:
Attachments
treasure island.zip
(181.81 KiB) Downloaded 4 times

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