Search found 2002 matches

by sweh
Thu Jan 17, 2019 3:53 pm
Forum: hardware
Topic: BBC Micro - Erratic Behaviour
Replies: 6
Views: 142

Re: BBC Micro - Erratic Behaviour

My BITD Beeb gave this horrible noise on Tuesday... I took the lid off and pressed down on components, and turned it on again... and it came to life. My guess is the cold in the basement may have made something come loose (perhaps the Solidisk 2M128 board that sits in the 6502 socket). Phew! Sometim...
by sweh
Wed Jan 16, 2019 12:21 am
Forum: software & utilities for the pc, mac or unix
Topic: Matrix Brandy BASIC V for Linux with SDL: V1.21.18 released
Replies: 460
Views: 17313

Re: Matrix Brandy BASIC V for Linux with SDL: V1.21.17 released

Another issue I've noticed is that, if you try to run a command in the background by putting a & on the end of the command, brandy still waits for the command to finish executing before proceeding. I would have expected it to continue executing immediately after the OSCLI, behaving the same as "sys...
by sweh
Tue Jan 15, 2019 5:57 pm
Forum: hardware
Topic: POLL: How much Sideways RAM?
Replies: 20
Views: 455

Re: POLL: How much Sideways RAM?

- Ctorwhy - I think this allows writes to the Flash direct? I seem to recall it causing problem for me? With the RAM/ROM board, the Winbond W29C020 flash chip has write protection built in, so a command sequence needs to be sent (anyone who followed MartinB's work will be familiar with this). But t...
by sweh
Tue Jan 15, 2019 12:51 am
Forum: hardware
Topic: I2C 4 U
Replies: 301
Views: 19318

Re: I2C 4 U

Heheheh
by sweh
Mon Jan 14, 2019 11:05 pm
Forum: hardware
Topic: I2C 4 U
Replies: 301
Views: 19318

Re: I2C 4 U

I think I've found a flaw... it causes your monitor to be displayed upside down!
by sweh
Mon Jan 14, 2019 4:57 pm
Forum: hardware
Topic: POLL: How much Sideways RAM?
Replies: 20
Views: 455

Re: POLL: How much Sideways RAM?

One "gotcha" is that some SWR banks don't necessarily become writeable the same way as on the Master. eg the original Solidisk SWR boards used the 6522 userport to determine write location. Most modern variations toggle write enable along with chip select (so writing the FE30 will enable that bank f...
by sweh
Mon Jan 14, 2019 2:08 pm
Forum: hardware
Topic: BBC Master grumpy sideways RAM detection
Replies: 39
Views: 471

Re: BBC Master grumpy sideways RAM detection

I've written a small test program that repeatedly reads location &8008 from slot 2 (the cartridge port) and the results do vary. I think what is actually being read back is the last byte of video data, floating on the data bus. In Mode 7 it's usually &20. In Mode 0 it's usually &00. Showing my hard...
by sweh
Mon Jan 14, 2019 12:59 am
Forum: hardware
Topic: BBC Master grumpy sideways RAM detection
Replies: 39
Views: 471

Re: BBC Master grumpy sideways RAM detection

FWIW, this is a very very simple tester. On a Master it should print RRRRWWWWRRRRRRRR. It correctly worked with my Master, my Solidisk 2M128 card, and the IFEL RAM/ROM (Flash) card. 10DIM D% 1000 20FOR A=0 TO 2 STEP 2 30P%=D% 40[OPT A 50SEI 60LDA &F4 70PHA 80LDY #0 90.LP 100STY &F4 110STY &FE30 120L...
by sweh
Sun Jan 13, 2019 9:11 pm
Forum: hardware
Topic: BBC Master grumpy sideways RAM detection
Replies: 39
Views: 471

Re: BBC Master grumpy sideways RAM detection

FWIW lda &8008 ; read byte eor #&AA ; invert, so that we are know we are writing a different value sta &8008 ; write byte cmp &8008 ; check that byte was written by comparing what we wrote with what we read back will misdetect some flash ROM as RAM. I hit this problem and had to put a sleep in there...
by sweh
Sun Jan 13, 2019 4:04 pm
Forum: hardware
Topic: POLL: How much Sideways RAM?
Replies: 20
Views: 455

Re: POLL: How much Sideways RAM?

My BITD B has a Solidisk 2M128 board (so 128K RAM, 128K ROM, with some not-quite-compatible shadow/buffer modes) . My second B has an IFEL board (so 128K RAM, 64K flash, 64K ROM). Both machines have a matchbox copro.
by sweh
Wed Jan 09, 2019 8:53 pm
Forum: general
Topic: Ideas please for BBC Micro splash screen
Replies: 51
Views: 981

Re: Ideas please for BBC Micro splash screen

Following the title is the ROM version number in ASCII terminated by a null. By convention, this is in the format 'major.minor' with two digits for the minor number. A convention not really well followed BITD, even by Acornsoft. eg VIEW had versions like A1.4 or A2.1, VIEWSHEET was 1.0, COMAL didn'...
by sweh
Tue Jan 08, 2019 2:11 am
Forum: general
Topic: Ideas please for BBC Micro splash screen
Replies: 51
Views: 981

Re: Ideas please for BBC Micro splash screen

flibble wrote:
Tue Jan 08, 2019 2:03 am
Reading the 'Acorn MOS' wiki article today jogged my memory, isn't there 768 bytes where the 'credits' are in the rom that could be used?
Pages FC, FD, FE... but on the A and B Beebs these are hard-mapped to Tom, Dick and Harry... err, Fred, Jim and Shiela, so can't be used for data or code.
by sweh
Tue Jan 08, 2019 1:05 am
Forum: off-topic
Topic: Xilinx lawyers
Replies: 15
Views: 441

Re: Xilinx lawyers

Since the guy (at 30 seconds) totally misrepresents the law ("this content is only for intended addressee" as a reason for not providing the letter - nope!), and since I can't see the video in question, I have trouble accepting at face value anything he says. I had written a long article on how many...
by sweh
Mon Jan 07, 2019 4:27 pm
Forum: programming
Topic: CRC Calculation
Replies: 11
Views: 244

Re: CRC Calculation

Coeus wrote:
Mon Jan 07, 2019 4:03 pm
BTW, which is the user guide to which you refer which contains this description?
The BBC MIcrocomputer User Guide; the one that came with the Beeb :-)
by sweh
Mon Jan 07, 2019 3:17 pm
Forum: programming
Topic: CRC Calculation
Replies: 11
Views: 244

Re: CRC Calculation

You forgot the *2 so the number is always even; (0x1f * 2 +1) EOR 2 and (0x1f *2) EOR 2 + 1 are both 61
by sweh
Mon Jan 07, 2019 2:34 pm
Forum: programming
Topic: CRC Calculation
Replies: 11
Views: 244

Re: CRC Calculation

Subtracting 65535 is the same as adding 1 (T=1?) In 16 bit. Yes, but I had to convince myself that changing the order of operations didn't cause any impact; that is "( crc EOR &810) * 2 + 1" was the same as "(crc *2 -65535) EOR &1020". It was late, last night, but this morning (after my first coffe...
by sweh
Mon Jan 07, 2019 1:53 am
Forum: programming
Topic: CRC Calculation
Replies: 11
Views: 244

Re: CRC Calculation

So I coded up a test program which I _think_ follows the algorithm more closely... sub Calc2($) { my $hl=0; foreach my $c (split(//,$_[0])) { $hl=(256*ord($c)) ^ $hl; foreach my $x (0..7) { my $t=0; if ($hl & 32768) { $hl ^= 0x810; $t=1; } $hl=($hl*2+$t) & 0xffff } } return $hl; } I then compared th...
by sweh
Mon Jan 07, 2019 1:30 am
Forum: programming
Topic: CRC Calculation
Replies: 11
Views: 244

Re: CRC Calculation

The user guide (page 399 says) The header CRC acts on all bytes from the filename to the spare bytes inclusive. The data CRC acts on the data only. CRCs are stored high byte first and are calculated as follows. In the following C represents the character and H and L represent the high and low bytes ...
by sweh
Fri Jan 04, 2019 3:02 pm
Forum: off-topic
Topic: What New Language Should I Learn?
Replies: 21
Views: 319

Re: What New Language Should I Learn?

I've started teaching myself GoLang... it's a compiled language but creates static binaries in most cases, which makes it easy to ship. You can also cross compile for Linux, Windows, MacOS so you don't even need those platforms :-)
by sweh
Fri Jan 04, 2019 12:37 am
Forum: hardware
Topic: Solidisk RTC
Replies: 5
Views: 175

Re: Solidisk RTC

Disassembling the RTC rom should show writes into the rom area. That’s my two cents :mrgreen: That's what I would expect, but how when the ROM socket is read-only and there is no flying lead to pick up the write line. Random guess: you could have the address space determine read or write e.g. if (f...
by sweh
Thu Dec 27, 2018 9:01 pm
Forum: introduce yourself
Topic: Hello from Atlanta, GA
Replies: 8
Views: 173

Re: Hello from Atlanta, GA

I know there is a few Beeb owners on the West Coast of the US, and a good group up in Canada. However not sure there is many of us here on the East Coast. I'm in New York... well, New Jersey, but I can see Manhattan from my office window :-) I've also been to Atlanta a couple of times recently (we ...
by sweh
Wed Dec 26, 2018 6:19 pm
Forum: general
Topic: Bit of fun - One change only
Replies: 64
Views: 1365

Re: Bit of fun - One change only

Kazzie wrote:
Wed Dec 26, 2018 5:50 pm
1024MAK wrote:
Wed Dec 26, 2018 5:12 pm
Where’s the smiley for boo, hiss...!

Mark
It's behind you! :P
Oh no it isn't!
by sweh
Tue Dec 25, 2018 2:42 am
Forum: projects
Topic: A new MENU system for MMC/Gotek/ (GOTEK working)
Replies: 55
Views: 1900

Re: A new MENU system for MMC/Gotek/ (GOTEK working)

I wonder if the build process might be easier if you start with MB's original DSDs, rather than trying to recombine them. Disk001->Disk129 contents come from those and they're fully packed and referenced in the CSV, anyway. So it'd only be the SSDs that didn't come from the MB disks that need to be ...
by sweh
Thu Dec 20, 2018 1:00 am
Forum: archive issues
Topic: STH archive not working?
Replies: 10
Views: 429

Re: STH archive not working?

The archive seems to be there ( http://www.stairwaytohell.com/bbc/archive/diskimages/ ) but the "reclist.php" page is return 500 errors ("server error").
by sweh
Mon Dec 03, 2018 2:39 am
Forum: general
Topic: How much of this is just rose-tinted specs?
Replies: 21
Views: 660

Re: How much of this is just rose-tinted specs?

Furthermore - with the level of integration and system on chip stuff there is not that much to look at when you tear down these new devices, if the functionality is not hidden behind some sealed unit its on some chip. People are not encouraged to tinker because of health and safety also. People of ...
by sweh
Sun Dec 02, 2018 3:34 am
Forum: projects
Topic: A new MENU system for MMC/Gotek/ (GOTEK working)
Replies: 55
Views: 1900

Re: (Just starting) A new MENU system for MMC/Gotek/?

Cool! Are you aware of what we call the spreadsheet ? Is there a CSV version of this? I was thinking of writing (in my copious free time) a menu front end to MB's "30th anniv" disk collection. I did a cruddy version, based purely off the menus on each disk, but something similar to the old STH menu...
by sweh
Wed Nov 28, 2018 2:08 pm
Forum: hardware
Topic: Waking up Mary
Replies: 10
Views: 457

Re: Waking up Mary

There's a lot of reasons... stiction, heat expansion, marginally aligned heads, luck...

Just 'cos it worked today doesn't mean it'll work tomorrow. Copy the data off ASAP :-)
by sweh
Sun Nov 25, 2018 3:45 pm
Forum: off-topic
Topic: USB HDD Behaviour
Replies: 6
Views: 259

Re: USB HDD Behaviour

I've seen external HDDs do this if the USB cable I was using was too thin and couldn't support the power requirements. It seems to work for a while but then looks like it's failing. Using a better USB cable solved that problem. You might also see this problem if your USB port is underpowered (common...
by sweh
Sat Nov 24, 2018 10:57 pm
Forum: programming
Topic: Shuffling a pack of cards
Replies: 17
Views: 596

Re: Shuffling a pack of cards

I'm representing the cards in C%(1-52) as eight bit numbers where the bottom two bits, 0-3, are the four suits and the top six bits (unsigned) hold the face value index of 1-52. Hence, a given card has a 0-3 suit of C%(n) AND 3 and a 1-13 face value of (C%(n) AND &FC)/4 I'm always interested in see...
by sweh
Mon Nov 19, 2018 10:22 pm
Forum: software: other
Topic: Updated BASIC Editor
Replies: 46
Views: 3665

Re: Updated BASIC Editor

IIRC, *SRLOAD opens the file reads byte by byte. So... do you get the same error if you use the "Q" flag to *SRLOAD? This is "quick" mode and loads the data into low memory then moves it into SWRam. What SSD ROM are you using? Some of the older ones have bugs that you might be hitting, especially si...