Search found 917 matches

by dp11
Thu Apr 18, 2019 6:34 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Prebuilt images and source code are now on github. https://github.com/dp111/Pi1MHz . The average user just needs to copy the firmware directory to the root of an SDCARD. Code needs some more comments and tidying ( help wanted) If someone want to add extra peripherals and doesn't understand how to fr...
by dp11
Wed Apr 17, 2019 9:10 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

nice
by dp11
Wed Apr 17, 2019 7:56 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 113
Views: 4072

Re: BeebSCSI 7_7

The another difference in the code between beebSCSI and Pi1MHz is that I use FatFS R0.13c which is the latest.
by dp11
Wed Apr 17, 2019 7:51 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Perfect, thanks! The BBC Master is my usual go-to machine, and these boards don't usually fit underneath. Whilst the converter is fine for the Model B, mounting on a Master might be a little more tricky from a signal quality perspective which is why I wanted to take a look at it. I'll put the desig...
by dp11
Wed Apr 17, 2019 7:32 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Circuits attached.
by dp11
Wed Apr 17, 2019 7:20 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Using diodes and resistors as a bidirectional level converter is a fairly standard trick (with caveats around pull-down): http://www.hobbytronics.co.uk/schottky-logic-level-conversion The advantage of the approach is that it's cheap; the disadvantage is that it skews the signal edges and doesn't wo...
by dp11
Tue Apr 16, 2019 8:00 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 113
Views: 4072

Re: BeebSCSI 7_7

Doesn't surprise me that TIME is inaccurate over long measurements (although, in this case, it's a very short measurement, so the inaccuracy should be less on average). My guess is the inaccuracy is the same per unit of transfer as the same number of IRQs will be missed for each transfer unit give ...
by dp11
Tue Apr 16, 2019 6:41 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 113
Views: 4072

Re: BeebSCSI 7_7

The speed test code on domesday86.com is very simple, it also measures the total operation time (as opposed to just the data transfer speed). The data transfer speed is much higher than quoted, but it's not really a practical measurement. Since BeebSCSI is open-source, I didn't feel the need to 'bu...
by dp11
Mon Apr 15, 2019 6:02 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 113
Views: 4072

Re: BeebSCSI 7_7

NB just for reference using TIME while ADFS access occurs is not accurate as IRQs are missed. TIME$ is accurate as that comes from the RTC.

The speed test on Domesday86 for BeebSCSI is likely to be incorrect.
by dp11
Mon Apr 15, 2019 5:54 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 113
Views: 4072

Re: BeebSCSI 7_7

Just as another data point. My quick test of Pi1MHz appears not to have a slow down ( I might have made a mistake)

My SDCARD might be quicker than yours as I see 11 reads per second or the difference is down to CPU speed difference.
by dp11
Mon Apr 15, 2019 12:37 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Is there a link to the PCB schematic and the source code? I don't like to plug anything new into my Acorn's unless I can see some schematics first :) Nice to see you've built upon my BeebSCSI code; I'm quite interested in how you did the CPLD part on the Pi; I'd been thinking about doing some Pi ba...
by dp11
Mon Apr 15, 2019 11:56 am
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Just doing a final stock count before saying yes to extra people. I've just shipped out orders in order people requested them from the beginning of the thread.
by dp11
Sun Apr 14, 2019 6:44 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Demand has exceeded supply !!! I have spare PCBs and resistors, but not diodes and connectors. I'll order some more
by dp11
Sat Apr 13, 2019 11:39 am
Forum: hardware
Topic: Master IO Controller IC15 - Databus pins?
Replies: 4
Views: 107

Re: Master IO Controller IC15 - Databus pins?

If you haven't see this thread , it might be worth a read . viewtopic.php?f=3&t=13964&p=184473&hilit=IC15#p184473
by dp11
Sat Apr 13, 2019 11:28 am
Forum: hardware
Topic: Master IO Controller IC15 - Databus pins?
Replies: 4
Views: 107

Re: Master IO Controller IC15 - Databus pins?

There are used to select between internal and external tube and 1MHz bus. ( fe34)
by dp11
Fri Apr 12, 2019 7:13 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Costs : PCBs £2 Kit of bits £2 ( except connectors and cable for 5v to the board and Pi) NB the 40way connector is currently made up of two 20way connectors and these need a little bit sanding off the side ( 0.5mm) Postage £1 for UK I'm not trying to make a profit from the above, but it you'd like t...
by dp11
Fri Apr 12, 2019 7:04 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Use real Adobe Acrobat read to see a 3d view of the PCB and parts
by dp11
Fri Apr 12, 2019 6:03 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Happy for you to post away.
by dp11
Fri Apr 12, 2019 5:41 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

No one has missed out. I haven't shipped any yet. This project should still be considered in Beta. If early people would like to PM me their details that would be great. Yes you can have an ADFS harddisc ( 512Mbytes), 480Mbytes of JIM RAM, and a M5000 at the same time. Currently if you do a ADFS acc...
by dp11
Thu Apr 11, 2019 7:34 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Now also emulates an ADFS harddisc. Read performance is about 100K/sec
by dp11
Thu Apr 11, 2019 4:54 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Music 5000 is also now supported. Even plays through the Beebs internal speaker.

If you use a RPI3B+ you can use the headphone jack for audio and get 992Mbytes of RAM to play with.
by dp11
Wed Apr 10, 2019 7:55 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 64
Views: 2347

Re: Raspberry Pi to 1MHz bus interface

Sorry for the delay. Lots of life got in the way.

I'm just getting ready to do a release.

Just to give you a hint of what is coming. The supported RAM via JIM is now 480MBytes ! hopefully that will be enough ( like 640K !) This RAM can also be preloaded from SDCARD.
by dp11
Fri Mar 29, 2019 8:47 pm
Forum: hardware
Topic: Watford User Port Splitter
Replies: 11
Views: 338

Re: Watford User Port Splitter

Risc PC uses an '04 and varies the supply voltage to make a vco for the pixel clock
by dp11
Thu Mar 28, 2019 11:37 pm
Forum: hardware
Topic: Watford User Port Splitter
Replies: 11
Views: 338

Re: Watford User Port Splitter

can't see how 3x 4066 would work .
by dp11
Thu Mar 28, 2019 11:29 pm
Forum: hardware
Topic: Watford User Port Splitter
Replies: 11
Views: 338

Re: Watford User Port Splitter

may be a 4 x 4053 ( 3 pole 2 way switch )?
by dp11
Sat Mar 23, 2019 7:02 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 113
Views: 4072

Re: BeebSCSI 7_7

I'm away from hardware at the moment.

Can you try adding filesystemFlush to the beginning of filesystemCheckLunDirectory .
by dp11
Fri Mar 15, 2019 10:12 pm
Forum: off-topic
Topic: Computing pi in a very unusual way
Replies: 10
Views: 408

Re: Computing pi in a very unusual way

This might be the most nutty way of computing PI

https://www.youtube.com/watch?v=HEfHFsfGXjs
by dp11
Wed Mar 13, 2019 12:47 pm
Forum: hardware
Topic: Master audio noise
Replies: 13
Views: 254

Re: Master audio noise

retroclinic is referring to the Main master circuit board and not the PSU.
by dp11
Mon Mar 11, 2019 7:24 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1124
Views: 106301

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

I was thinking of dropping pi 1 , but we could say limit copros to 240Mbytes . I don't really want another build.
by dp11
Mon Mar 11, 2019 6:45 pm
Forum: hardware
Topic: Pi-based Co-Pro on the cheap - 100MHz 6502 for £10? (now 274MHz)
Replies: 1124
Views: 106301

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

It has been on my list to re organise the ram to enable larger memory , but with no actual requirement till now it has been at the bottom of my todo list.