Search found 6008 matches

by 1024MAK
Sat Apr 29, 2017 12:50 am
Forum: wanted
Topic: Wanted: 4 x Waffle tray for 14mm x 144mm x 1,4mm TQFP
Replies: 5
Views: 49

Re: Wanted: 4 x Waffle tray for 14mm x 144mm x 1,4mm TQFP

Sorry Dave, the only Waffle related thing I can offer is this:



Mark
by 1024MAK
Sat Apr 29, 2017 12:10 am
Forum: general
Topic: Scanning manuals
Replies: 2
Views: 43

Re: Scanning manuals

xsane can do OCR. But sometimes it's fair and other times it's not so good... I used xsane and a flatbed scanner to scan a booklet a while ago. I have also scanned A4 manuals before and it goes get rather tiresome after many pages. So do it in stages and take breaks ;-) Of course, once you have the ...
by 1024MAK
Fri Apr 28, 2017 7:53 pm
Forum: hardware
Topic: Why so few off-shelf All in one video ICS (ie 6847, Tms9918 descendants
Replies: 17
Views: 299

Re: Why so few off-shelf All in one video ICS (ie 6847, Tms9918 descendants

I think using a 6845 with a more complex colour palette system and shadow RAM would have been the business, but improving the video and graphics was not the objective. It's not that hard to use 1980s technology to build a better graphics system. The limiting factors are cost (for a mass produced ite...
by 1024MAK
Fri Apr 28, 2017 7:35 pm
Forum: software: other
Topic: BBC BASIC: nearly had no line number. could it have saved space by virtual line no's?
Replies: 14
Views: 134

Re: BBC BASIC: nearly had no line number. could it have saved space by virtual line no's?

During Computer Studies at school in the early 1980s, we got to write BASIC programs that were batch processed on a mainframe somewhere (I forget where). The program had to be written on special forms and line numbers were required. The lines also had to be in the correct order. Very few of us in th...
by 1024MAK
Fri Apr 28, 2017 7:26 pm
Forum: software: other
Topic: BBC BASIC: nearly had no line number. could it have saved space by virtual line no's?
Replies: 14
Views: 134

Re: BBC BASIC: nearly had no line number. could it have saved space by virtual line no's?

If you want to see a BASIC like language without line numbers, OPL on the Psion Series 3, 3a, 3c, 3mx, 5, 5mx is very good.

Mark
by 1024MAK
Fri Apr 28, 2017 6:20 pm
Forum: general
Topic: Ceefax / Fastext Question
Replies: 9
Views: 869

Re: Ceefax / Fastext Question

I think it depended on the TV set. Memory for five pages was the minimum for fastext (currently displayed page plus either the four highlighted coloured links or with some sets, four user selectable pages). Apparently later TV sets could capture more pages, so you could type in the page number, and ...
by 1024MAK
Fri Apr 28, 2017 2:34 pm
Forum: off-topic
Topic: how to desolder pcb boards ?
Replies: 6
Views: 98

Re: how to desolder pcb boards ?

I too use an electric paint stripper. The hot air gun on soldering stations could also be used. The key is to keep moving it so that the board and the components you are interested in, heat up slowly and evenly. Through hole components will sometimes drop out. But often they need some help if the ho...
by 1024MAK
Fri Apr 28, 2017 2:13 pm
Forum: hardware
Topic: Electron Cassette I/O
Replies: 16
Views: 202

Re: Electron Cassette I/O

The time constant appears to be too long (too slow) to be any thing to do with baud rate or tone frequency.

Could be a tone detected / lack of tone timer though.

Mark
by 1024MAK
Fri Apr 28, 2017 2:01 pm
Forum: hardware
Topic: Electron Cassette I/O
Replies: 16
Views: 202

Re: Electron Cassette I/O

(what's that pin labelled CAS RC doing? Is that an input or an output?? Is it some kind of external time reference???) Some time delay reference by the look of it. Definitely an input. May or may not also be an output. If pin 64 (CAS MO) can drive low, when this pin is low, it will discharge C8. Wh...
by 1024MAK
Fri Apr 28, 2017 1:32 pm
Forum: hardware
Topic: Electron Cassette I/O
Replies: 16
Views: 202

Re: Electron Cassette I/O

Yes! :D

Thanks Dave =D>

Mark
by 1024MAK
Fri Apr 28, 2017 1:27 pm
Forum: off-topic
Topic: Why are domino plugs reversible?
Replies: 4
Views: 114

Re: Why are domino plugs reversible?

With regard to RS232 usage... As a printer is not DCE (data communications equipment), it should have been wired up as a DTE (data terminal equipment). Before computers became common and affordable, "dumb" VDU terminals and "line" printers were often connected via serial connecti...
by 1024MAK
Fri Apr 28, 2017 12:29 pm
Forum: hardware
Topic: Palettemate / enhanced video ULA with 4096 colours
Replies: 166
Views: 5019

Re: Palettemate / enhanced video ULA with 4096 colours

Looking forward to this. Very exciting news :D

Mark
by 1024MAK
Fri Apr 28, 2017 10:57 am
Forum: hardware
Topic: Electron Cassette I/O
Replies: 16
Views: 202

Re: Electron Cassette I/O

The cassette input to the Elk. First we have resistor R64 (10k) and diodes D6 and D7, then C26 (1.5nF). The resistor and diodes limit any input voltage (after the resistor) to +5V and -5V. The R64 and C26 act as a low pass filter with a roll off of 10kHz, so this limits the high frequencies. Then th...
by 1024MAK
Fri Apr 28, 2017 10:43 am
Forum: hardware
Topic: Electron Cassette I/O
Replies: 16
Views: 202

Re: Electron Cassette I/O

All component references are for the issue 4 schematic that I'm looking at. It's not a very good copy, so if anyone knows of a better copy, or differences for the other Elk PCB versions, please point me in the correct direction ;-) For the Elk output to cassette, there is a simple filter (R23, R28 a...
by 1024MAK
Fri Apr 28, 2017 10:00 am
Forum: hardware
Topic: USB Electron Cartridge Interface
Replies: 6
Views: 202

Re: USB Electron Cartridge Interface

I haven't been able to find a way to tell the Electron to ignore cartridges on boot, which means that a cartridge containing code that causes a crash on startup is effectively bricked unless you have an external programmer like this. The normal way of doing this in hardware, is to have a two pin he...
by 1024MAK
Fri Apr 28, 2017 9:27 am
Forum: hardware
Topic: USB Electron Cartridge Interface
Replies: 6
Views: 202

Re: USB Electron Cartridge Interface

sirmorris wrote: =D> nice board!

Yep :D. An interesting idea \:D/

Mark
by 1024MAK
Fri Apr 28, 2017 9:23 am
Forum: hardware
Topic: Electron Cassette I/O
Replies: 16
Views: 202

Re: Electron Cassette I/O

As there is a separate thread about the USB Electron Cartridge Interface, please be sensible in staying on topic. You can always include a link between topics / posts.

@David - nice idea =D>. I look forward to seeing what else can be achieved with the cassette port :D.

Mark
by 1024MAK
Fri Apr 28, 2017 12:04 am
Forum: general
Topic: Today I built ...
Replies: 17
Views: 320

Re: Today I built ...

Use the flux! I have never used any additional flux for soldering through-hole components.... And the second rule of soldering is... Oh wait, I already talked about it... To be fair, if you are using brand new clean components on a new (and clean, and that means no sticky finger marks) PCB, you sho...
by 1024MAK
Thu Apr 27, 2017 11:53 pm
Forum: hardware
Topic: Why so few off-shelf All in one video ICS (ie 6847, Tms9918 descendants
Replies: 17
Views: 299

Re: Why so few off-shelf All in one video ICS (ie 6847, Tms9918 descendants

...To support their own μP, they also produced various support chips. These support chips included parallel interface control chips, serial UART chips, sound chips, keyboard interface chips, DRAM controller chips, PROM, SRAM, DRAM, interrupt controllers, timers, clock generators and video display c...
by 1024MAK
Thu Apr 27, 2017 11:35 pm
Forum: for sale / freebies
Topic: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE
Replies: 80
Views: 1812

Re: ELECTRON User Port & ROM/RAM Board with UPURS - NOW AVAILABLE

[ state the obvious ] When fault finding, it's wise to check that any suspect chips have power on their power pins and that 0V/ground pin(s) are/is actually connected to the the system 0V [/ state the obvious ] :lol: Roland, good that your EUP board is now working okay :D Yes. Martin did say (somewh...
by 1024MAK
Thu Apr 27, 2017 6:25 pm
Forum: off-topic
Topic: Why are domino plugs reversible?
Replies: 4
Views: 114

Re: Why are domino plugs reversible?

DIN is a German standard ( link ). 3 pin DIN plugs (mono in / out) may have been deliberately designed to fit in 5 pin 180 o sockets. 5 pin are for stereo in / out. Because round DIN plugs are often used for audio use. Another example is the 2 pin DIN connecter, it is often used for speaker connecti...
by 1024MAK
Thu Apr 27, 2017 6:18 pm
Forum: hardware
Topic: Why so few off-shelf All in one video ICS (ie 6847, Tms9918 descendants
Replies: 17
Views: 299

Re: Why so few off-shelf All in one video ICS (ie 6847, Tms9918 descendants

As I recall the ZX81 is another instance of the "Cheap Video" technique used in my KimKlone -- ie, force a NOP or similar onto the microprocessor data bus so it'll consecutively fetch a string of bytes and thus produce the addresses required for the data fetches for a hortizontal scan lin...
by 1024MAK
Thu Apr 27, 2017 3:24 pm
Forum: general
Topic: Today I built ...
Replies: 17
Views: 320

Re: Today I built ...

Soldering tip I read recently: Don't try to use the soldering iron like a paint brush. It's not for delivering solder to the joint, it's for heating the two things to be joined. Then you feed solder on to the hot things. (The tinning of the iron is just to improve the heat transfer to the things. L...
by 1024MAK
Thu Apr 27, 2017 2:35 pm
Forum: hardware
Topic: Why so few off-shelf All in one video ICS (ie 6847, Tms9918 descendants
Replies: 17
Views: 299

Re: Why so few off-shelf All in one video ICS (ie 6847, Tms9918 descendants

In the 1970s and early 1980s, a large number of semiconductor companies were producing, or intending to produce 8 bit μPs or MPs ( Microprocessors - see note). To support their own μP, they also produced various support chips. These support chips included parallel interface control chips, serial UAR...
by 1024MAK
Wed Apr 26, 2017 11:59 pm
Forum: hardware
Topic: Retrobriting my Master case
Replies: 21
Views: 402

Re: Retrobriting my Master case

by 1024MAK
Wed Apr 26, 2017 10:14 am
Forum: wanted
Topic: Turtle LOGO for BBC Compact
Replies: 8
Views: 120

Re: Turtle LOGO for BBC Compact

Most USB floppy drives will only work with "IBM" PC MSDOS formats :(

Mark
by 1024MAK
Wed Apr 26, 2017 7:06 am
Forum: general
Topic: Today I built ...
Replies: 17
Views: 320

Re: Today I built ...

Resistor calculators: digikey.co.uk or hobby-hour.com . There are also apps for iPhones, iPads, etc... When trying to read resistor colour codes, natural daylight is best. Note that some CFL and LED lamps have a poor colour index, and so some resistor band colours look the wrong colour :( The first ...
by 1024MAK
Tue Apr 25, 2017 10:04 pm
Forum: hardware
Topic: Retrobriting my Master case
Replies: 21
Views: 402

Re: Retrobriting my Master case

Definitely looks better than it did. Well done =D>

Retrobriting is something I have not yet tried.

Mark
by 1024MAK
Tue Apr 25, 2017 10:02 pm
Forum: hardware
Topic: Being silly with floppy discs
Replies: 9
Views: 207

Re: Being silly with floppy discs

Don't worry, I think everyone has trouble with formatting disks at first :roll: Back in the 1980s at school, there was no Internet to help. I forget now if the school had all the documentation. Anyway, anything the teacher did not know, I had to work out for myself. Or go to the towns main library.....

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