Search found 2011 matches

by sweh
Fri Mar 15, 2019 10:58 pm
Forum: off-topic
Topic: Computing pi in a very unusual way
Replies: 7
Views: 239

Re: Computing pi in a very unusual way

Important part of this algorithm is that "int" is the "floor" function. So int(-20/19) is -2, but int (20/19) is 1.
by sweh
Sun Mar 10, 2019 1:10 am
Forum: hardware
Topic: Rom daughterboard
Replies: 19
Views: 469

Re: Rom daughterboard

I would expect the BASIC ROM to be in one of the original 4 banks sitting underneath this expansion board since I don't see it in the picture.

When your expansion board wasn't sitting properly (a _common_ issue) the mainboard probably couldn't decode the addresses properly to find it
by sweh
Sun Mar 10, 2019 12:58 am
Forum: hardware
Topic: Rom daughterboard
Replies: 19
Views: 469

Re: Rom daughterboard

"Language?" means that it couldn't find any language ROM to boot into. Which _probably_ means it can't read any of the ROMs.
by sweh
Sat Mar 09, 2019 5:52 pm
Forum: hardware
Topic: Turbo MMC Problem
Replies: 17
Views: 344

Re: Turbo MMC Problem

Do I use like *SRLOAD MMFS 0E00 Q I 5 which I did try and nothing loaded in roms. Which version I sould use from the page? You will want the T/MAMMFS version ("TurboMMC, Master") as described at https://github.com/hoglet67/MMFS/wiki/Release-structure To load it you will use a command similar to *SR...
by sweh
Sat Mar 09, 2019 2:18 am
Forum: hardware
Topic: Turbo MMC Problem
Replies: 17
Views: 344

Re: Turbo MMC Problem

Since you have a Master, you may find using the Master version of MMFS ( https://github.com/hoglet67/MMFS/releases ) might work better for you. It's based on a newer version of DFS, has optimizations for the TurboMMC hardware, has a number of bug fixes, and uses Master workspace, to keep page at &0E...
by sweh
Mon Feb 25, 2019 6:37 pm
Forum: programming
Topic: Extended key numbering (OSbyte &8A)
Replies: 5
Views: 164

Re: Extended key numbering (OSbyte &8A)

129 is shift+f1 OSByte &EA, as mentioned at http://central.kaserver5.org/Kasoft/Typeset/BBC/Ch42.html OSBYTE call with A=&EA (228) Set base number for SHIFT-function-key codes Pressing one of the function keys while the SHIFT key is pressed will normally in release 1.0 produce ASCII codes in the ran...
by sweh
Sat Feb 23, 2019 4:35 pm
Forum: hardware
Topic: BBC - PC Serial link
Replies: 19
Views: 416

Re: BBC - PC Serial link

Dunno if this helps, but attached is an SSD image with a Kermit ROM and another version that runs from main memory (&2000). This can help check the serial cable is working.
by sweh
Thu Feb 07, 2019 2:07 pm
Forum: software: other
Topic: BASIC Tokenizer
Replies: 7
Views: 454

Re: BASIC Tokenizer

Is there an easy way to tokenize plain text BASIC files? Something like a windows or linux command line tool. Maybe http://www.retrosoftware.co.uk/wiki/index.php/BASIC_tokeniser/detokeniser_in_C would help? BASIC Tokeniser/Detokeniser Some C++ (but trivial to convert into C) routines that convert t...
by sweh
Tue Feb 05, 2019 11:56 pm
Forum: software: other
Topic: BBC *Status Command (and odd characters)
Replies: 24
Views: 552

Re: BBC *Status Command (and odd characters)

In mode 7, sequences like char(131) cause a colour change _and_ take a character on the screen. It's a consequence of how Teletext works. Programmers know this and take the extra character into account when lining things up on the screen. Of course teletext sequences don't mean much to printers, sin...
by sweh
Thu Jan 17, 2019 3:53 pm
Forum: hardware
Topic: BBC Micro - Erratic Behaviour
Replies: 9
Views: 387

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: V1.21.19 released
Replies: 520
Views: 21435

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: 595

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: 372
Views: 22549

Re: I2C 4 U

Heheheh
by sweh
Mon Jan 14, 2019 11:05 pm
Forum: hardware
Topic: I2C 4 U
Replies: 372
Views: 22549

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: 595

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: 612

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: 612

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: 612

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: 595

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: 1268

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: 1268

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: 622

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: 371

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: 371

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: 371

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: 371

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: 371

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: 480

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: 221

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: 294

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 ...