Search found 1923 matches

by sweh
Mon Jul 16, 2018 3:36 pm
Forum: hardware
Topic: 2nd User port for Beeb?
Replies: 96
Views: 6182

Re: 2nd User port for Beeb?

I did indeed design BeebSID to fit in to an already very congested and contested page $FC but it significantly pre-dates the second user port and the latter technically conflicts with existing legacy usage but there always has to be pragmatic thinking and compromise with these things. Yeah, I just ...
by sweh
Mon Jul 16, 2018 12:55 pm
Forum: hardware
Topic: 2nd User port for Beeb?
Replies: 96
Views: 6182

Re: 2nd User port for Beeb?

The two 74LS chips act as an address decoder, selecting banks of 32 bytes at a time. In the default configuration it uses &Fc00-&Fc1f but that can be changed by modifying one link. Not sure what addresses BeebSID are used at. As long as they don't conflict then they can both be used at the same time.
by sweh
Tue Jun 26, 2018 12:38 am
Forum: hardware
Topic: My Turbo MMC Misadventures
Replies: 35
Views: 829

Re: My Turbo MMC Misadventures

Confession... back in the day I used to use the "bottle opener" blade of my pen knife to remove ROMs. The rounded edge of the back of the blade made a nice lever against the motherboard. It looked something like this:
bottle-opener.jpeg
bottle-opener.jpeg (6.14 KiB) Viewed 267 times
I didn't bend too many pins, and never broke any :-)
by sweh
Tue Jun 26, 2018 12:21 am
Forum: emulators
Topic: When should keyboard interrupts be enabled during startup?
Replies: 7
Views: 619

Re: When should keyboard interrupts be enabled during startup?

1. Bootup. - Memory is cleared to 0, by a loop that hits here: Well, mostly. The zero'th byte of each page isn't cleared. This is because the OS initally writes RTI to &D00 so any stray NMIs return, and _then_ it cleans out memory...without clearing the RTI. See &D9CD, which is where (&FFFC) points...
by sweh
Mon Jun 18, 2018 1:10 pm
Forum: stardot.org.uk
Topic: Post Edits
Replies: 36
Views: 1252

Re: Post Edits

People will _always_ complain about changes, no matter how minor; That’s incredibly patronising Stephen and overtly implies that anyone who objects to this or any other change to the forum mechanisms isn’t capable of intelligent comment and argument. That you wrote this and also excluded the "chees...
by sweh
Mon Jun 18, 2018 12:35 am
Forum: stardot.org.uk
Topic: Post Edits
Replies: 36
Views: 1252

Re: Post Edits

I've never liked the traditional behaviour, but didn't care enough to complain or even comment on it.

People will _always_ complain about changes, no matter how minor; it's all about moving of cheese
by sweh
Sun Jun 10, 2018 3:17 am
Forum: programming
Topic: left and right brackets on beebem
Replies: 7
Views: 310

Re: left and right brackets on beebem

mode 8 seems to work. thanks for the help By default, the Beeb has MODE 0->7. Mode 8 would be the equivalent of mode 0. (There's a theoretical mode 8 documented in the AUG, which is achieved by direct programming of the video chips, but it's not a supported mode). With the Beeb, Modes 0->6 are bitm...
by sweh
Mon May 28, 2018 6:24 pm
Forum: archive requests
Topic: ROM based games by STL
Replies: 5
Views: 246

Re: ROM based games by STL

Rat Race appears to have been based on the STL "Sprite" ROM and "Tune" ROM (I don't see it on disks STL1-10, but I have a copy). Other than that, it's just a BASIC program copied into SWR. How does a BASIC program run from SWR given that the BASIC interpreter would be occupying the same address spa...
by sweh
Mon May 28, 2018 5:15 pm
Forum: off-topic
Topic: Forum GDPR compliance?
Replies: 58
Views: 896

Re: Forum GDPR compliance?

Odd; I got the GDPR interstitial again today, despite having accepted it yesterday...
by sweh
Sat May 26, 2018 11:03 am
Forum: archive requests
Topic: ROM based games by STL
Replies: 5
Views: 246

Re: ROM based games by STL

Rat Race appears to have been based on the STL "Sprite" ROM and "Tune" ROM (I don't see it on disks STL1-10, but I have a copy). Other than that, it's just a BASIC program copied into SWR.

I've just checked all my disks and I don't appear to have anything else using the Sprite ROM.
by sweh
Fri May 11, 2018 12:08 am
Forum: off-topic
Topic: Need some electronics advice...
Replies: 20
Views: 818

Re: Need some electronics advice...

So I could buy 1 diode for around $1. Or I can buy 400 for $8.

I now have so many diodes I can rectify the world. (Hmm, maybe all of them together will rectify that Brexit idiocy?).

Hopefully I'll have time this weekend to try it out.
by sweh
Sun May 06, 2018 2:28 pm
Forum: off-topic
Topic: Need some electronics advice...
Replies: 20
Views: 818

Re: Need some electronics advice...

The transistor would work as a drop-in replacement for the relay, yeah. It doesn't prevent the need for the diode over the solenoid, though :-(
by sweh
Sun May 06, 2018 1:29 pm
Forum: off-topic
Topic: Need some electronics advice...
Replies: 20
Views: 818

Re: Need some electronics advice...

The initial link to my site goes into a bit more detail but, to make it simple, I wanted to replace the original (broken) controller board with an Arduino Nano. That'd let me do more "computer control" of the safe via a serial port. Because I was pretty sure the Arduino wouldn't be able to supply en...
by sweh
Sun May 06, 2018 1:30 am
Forum: off-topic
Topic: Need some electronics advice...
Replies: 20
Views: 818

Re: Need some electronics advice...

I can't tell what solenoid it is; it's very wrapped up ( https://www.sweharris.org/Safe/large/internals.jpg ). I can find lots of pictures, but I can't find any actual specs. I've seen some for sale on aliexpress claiming to be 6V 0.35A ( https://www.aliexpress.com/item/Solenoid-for-Safe-Lock-Compat...
by sweh
Sat May 05, 2018 9:28 pm
Forum: off-topic
Topic: Need some electronics advice...
Replies: 20
Views: 818

Re: Need some electronics advice...

Looking through my box of randomness, the only diode type I have is 1N914. I've also got a bunch 0.1uF 50V capacitors.

It's funny that two components, so small, can make such a difference :-)
by sweh
Tue May 01, 2018 4:11 pm
Forum: off-topic
Topic: Need some electronics advice...
Replies: 20
Views: 818

Re: Need some electronics advice...

I now have a weekend project :-)

Thanks!
by sweh
Tue May 01, 2018 10:19 am
Forum: off-topic
Topic: Need some electronics advice...
Replies: 20
Views: 818

Re: Need some electronics advice...

Thanks for the replies! If I understand correctly, then I should put a diode between VCC and GND on the input to the relay side, with the cathode on VCC and the anode on GND. That's easy enough. Similarly another one between ON and GND on the output of the relay. Should the capacitors be in the same...
by sweh
Mon Apr 30, 2018 11:23 pm
Forum: off-topic
Topic: Need some electronics advice...
Replies: 20
Views: 818

Need some electronics advice...

As previously mentioned, I used an arduino to replace a broken electronic safe controller and made it computer controlled instead: https://www.sweharris.org/post/2017-10-09-digital_safe/ The circuit design is pretty simple: https://www.sweharris.org/Safe/large/diagram.jpg But recently I've been havi...
by sweh
Wed Apr 18, 2018 10:38 pm
Forum: software & utilities for the pc, mac or unix
Topic: New Disk Image Editor
Replies: 76
Views: 3111

Re: New Disk Image Editor

I wonder if we can create something that's backwards compatible. I wonder how many tools currently read the _second_ line of the INF file? So we could have FOO_BAR load exec Locked V2 NAME:FOO BAR v2 aware code can look for the second line and if it's V2 then read the 3rd line for NAME: then use th...
by sweh
Wed Apr 18, 2018 2:02 am
Forum: software & utilities for the pc, mac or unix
Topic: New Disk Image Editor
Replies: 76
Views: 3111

Re: New Disk Image Editor

And you can put filenames in "" so e.g. a improvement could be something like this, which is invalid as regular inf, and thus utilities not updated for this will/should give an error message, but bbcim and other utilities could be changed to incorporate this in the next version and then do the righ...
by sweh
Mon Apr 16, 2018 12:46 am
Forum: other vintage computer hardware, software and games
Topic: A special day for a very special computer!
Replies: 13
Views: 875

Re: A special day for a very special computer!

I think you have to remember that, when it was released, the closest most people came to a computer was when they received their payslip, bank statement or telephone bill which had been printed by a mainframe. When I first saw a microcomputer, the ZX81's pre-decessor, the ZX80, it was the only comp...
by sweh
Fri Mar 30, 2018 1:34 am
Forum: programming
Topic: BASIC 2 string arrays
Replies: 4
Views: 364

Re: BASIC 2 string arrays

FWIW, the "BASIC ROM user guide" (OCR'd here http://stardot.org.uk/forums/viewtopic.php?t=13861) and "Advanced BASIC ROM user guide" ( http://stardot.org.uk/forums/viewtopic.php?f=42&t=13860 ) are invaluable resources on how BASIC works. It's been decades (literally) since I last read them so I don'...
by sweh
Thu Mar 29, 2018 11:18 am
Forum: software & utilities for the pc, mac or unix
Topic: New Disk Image Editor
Replies: 76
Views: 3111

Re: New Disk Image Editor

I realise that it's a "standard" that's been used for forever, but I would add my two penneth by suggesting it's a standard that I've not had to worry about since about 1998 - in fact I've actively avoided using anything that saves files like that simply as it's so messy. Why not support both optio...
by sweh
Mon Mar 26, 2018 10:56 pm
Forum: hardware
Topic: read out 23128 rom
Replies: 7
Views: 480

Re: read out 23128 rom

Well, it's definitely a variation of BASIC 1, based on the copyright and that it only has OPENIN/OPENOUT (no OPENUP). Doing a binary compare to a version of BASIC1 that I had BITD I can see it's not the same eg at A63 your ROM has had another byte added 0a63 0D 53 S 0a64 53 S 54 T 0a65 54 T 4F O 0a6...
by sweh
Sun Mar 25, 2018 3:46 am
Forum: hardware
Topic: HostFS and microcontrollers?
Replies: 48
Views: 3139

Re: HostFS and microcontrollers?

Out of interest do you use &9B or &7F as <esc> on your controller? Hmm, when did the Serial Tube escape character change? My code was based on JGH's original routines which had 600 esc=&7F Interesting; I see the "protocol" document has changed. Previously it read An escape byte must be chosen so as...
by sweh
Sun Mar 25, 2018 3:21 am
Forum: hardware
Topic: HostFS and microcontrollers?
Replies: 48
Views: 3139

Re: HostFS and microcontrollers?

Ah... this thread now explains why Dave PM'd me on this topic ;-) (I've been busy so not been keeping up with this forum for a few weeks). It all makes sense, now! Martin, this looks like the race condition I pointed out to you way back when (2013, according to my email history... wow that was a lon...
by sweh
Fri Mar 16, 2018 1:35 pm
Forum: off-topic
Topic: Elite for Emacs
Replies: 1
Views: 357

Re: Elite for Emacs

... and "Elite the Musical". https://youtu.be/y-hxWLoOjgw
by sweh
Fri Mar 16, 2018 1:31 pm
Forum: off-topic
Topic: Elite for Emacs
Replies: 1
Views: 357

Elite for Emacs

http://sami.salkosuo.net/elite-for-emacs/

For that time you want to do intergalatic trading via your text editor...
by sweh
Wed Mar 14, 2018 11:18 am
Forum: development tools
Topic: BeebAsm
Replies: 73
Views: 5273

Re: BeebAsm

On Linux /usr/include/math.h has

Code: Select all

# define M_PI          3.14159265358979323846  /* pi */
Is there no equivalent on OpenBSD?
by sweh
Wed Mar 14, 2018 2:04 am
Forum: software: other
Topic: Wanted: ENFS
Replies: 9
Views: 858

Re: Wanted: ENFS

That's funny.... "Supplied to The Isle College, Wisbech". My cousins live just 17 miles away from there (Cowbit). I may have been in that town once or twice, as a kid.