Search found 484 matches

by simoni
Fri Aug 16, 2019 11:55 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

Hoglet's board is a 7_5 PCB - the 7_7s have a more compact Molex microSD socket that's easier to solder (7_7 is the current PCB release version).
by simoni
Fri Aug 16, 2019 11:12 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

If they are soldered correctly, you would need a silly amount of force to break the solder; try pulling a SMT cap off a board without heating it and you'll find out just how strong solder is. Basically, if you don't heat both the PCB pad and the pin of the component you will end up flowing solder on...
by simoni
Fri Aug 16, 2019 4:01 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

Great. Also you should upgrade the firmware; 2.5 is the current version (and contains some nice performance improvements for big files).
by simoni
Thu Aug 15, 2019 2:41 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

Didn't miss anything; I was just explaining that the test was simple to do (and that; if you have issues - reading the trace will tell you what they are; saving a whole bunch of speculation and time). BeebMaster - There are two common construction faults - one is the soldering around the SD card (wh...
by simoni
Thu Aug 15, 2019 2:14 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

As I already mentioned; you can simply CTRL+break the Beeb with the trace on. The trace will state if the card is detected. If it's not; there's your hardware fault. You don't even need a multimeter to know (although it's a pretty easy test as you have a schematic for the board and it shows that the...
by simoni
Thu Aug 15, 2019 11:42 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

It's almost certainly hardware related; only the snippet of the log file misses the important bit (which is from when the SD card is detected). I'm almost certain that the card detect switch isn't soldered properly; however, if you could post the log including the bit when the BeebSCSI starts (or ju...
by simoni
Thu Aug 15, 2019 10:58 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

What error does the Beeb give when you try to access the LUN?

Edit: If you could also link to the BeebSCSI trace, that would be great.
by simoni
Thu Aug 15, 2019 10:37 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

Doesn't make much sense... if you have a BeebSCSI and an SD card; you just copy the quick-start LUN to the SD card (as per the doc) and boot the BBC. Once you have loaded SuperForm you can even use it to format the current LUN; or you can load it; *SCSIJUKE, change LUN sets completely; then OLD, RUN...
by simoni
Thu Aug 15, 2019 10:19 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

Just download the quick start LUN image from the following link: https://www.domesday86.com/?page_id=400 You can either a) use the quick start LUN image, mount it and use the superform image to format other LUNs, or b) copy it to a floppy from there (or Gotek) or c) use ADFS explorer to move superfo...
by simoni
Sat Aug 03, 2019 1:53 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

I usually boot dos, load gem and draw a picture of Ian.
The Ian-test is a solid one, I use it for testing SmallyMouse2 boards too :)
ian.jpg
by simoni
Sat Aug 03, 2019 1:32 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

My usual soak test is to run the speedtest BASIC program available from the Domesday86 site. I run it reading and writing for a couple of minutes; then I remove the write command and run it again just reading the same file over and over again for 30 minutes or so. If nothing odd happens, the board i...
by simoni
Sat Aug 03, 2019 11:48 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

The reports in the latter parts of this thread are primarily to do with bug and issues around the RaspPi implementation of the firmware - the hardware version 7_5 and 7_7 board's firmware has been widely tested (and any small issues ironed out). It would have been good if dp11 could have confirmed w...
by simoni
Sun Jun 23, 2019 8:29 pm
Forum: software: other
Topic: The Stappenmaster Domesday Disc...
Replies: 6
Views: 612

Re: The Stappenmaster Domesday Disc...

The patterning on the surface of the disc and the CLV format are the tells that it's for calibration; there are a number of similar examples of such laserdiscs produced for internal R&D and manufacturing purposes. The VP415 was developed specifically for Domesday, so the label isn't surprising (see ...
by simoni
Sun Jun 23, 2019 4:04 pm
Forum: software: other
Topic: The Stappenmaster Domesday Disc...
Replies: 6
Views: 612

Re: The Stappenmaster Domesday Disc...

There were no Domesday prototypes that used Teletext as far as all first-person and documented accounts show. The BBC produced the commercial Garden Birds disc which contained teletext as an experiment in interactive video (which was successful) - the success of that was used to prove the early viab...
by simoni
Tue Jun 11, 2019 8:21 pm
Forum: hardware
Topic: Data Center Discontinued?!
Replies: 13
Views: 793

Re: Data Center Discontinued?!

It's also worth mentioning that BeebSCSI was designed from scratch to be an open-design; both the hardware and the firmware in the solution are fully documented, not just from the user's perspective, but also from a technical implementation too. Plus BeebSCSI isn't a patched IDE implementation with ...
by simoni
Thu Jun 06, 2019 4:56 pm
Forum: hardware
Topic: BBC Master 128 schematic in KiCAD
Replies: 17
Views: 923

Re: BBC Master 128 schematic in KiCAD

Good point, I'll fix it next time I'm working on the schematic (as it's pretty minor)
by simoni
Thu Jun 06, 2019 4:44 pm
Forum: hardware
Topic: BBC Master 128 schematic in KiCAD
Replies: 17
Views: 923

Re: BBC Master 128 schematic in KiCAD

The RTC part number has been updated and the revised version is now on github.
by simoni
Thu Jun 06, 2019 11:47 am
Forum: hardware
Topic: BBC Master 128 schematic in KiCAD
Replies: 17
Views: 923

Re: BBC Master 128 schematic in KiCAD

I just checked an issue 1 Master PCB and pins 1 and 16 are not connected. The chip markings (removed from the same issue 1 board) state "MC146818P". The original schematic only says 146818 and the chip datasheet for the MC146818P states that 1 and 16 are NC. So I'd conclude that both the new schemat...
by simoni
Wed May 01, 2019 5:06 pm
Forum: hardware
Topic: Issue 4 Beeb - Modification
Replies: 2
Views: 227

Re: Issue 4 Beeb - Modification

At a glance I'd say it was to modify the VREF voltage to the ADC IC (the diodes are used to drop the voltage from the 5V supply). Since D6,7 and 8 are most likely still in place, you can safely remove it (leaving it in place will probably cause analogue joysticks to have a modified swing).
by simoni
Sun Apr 28, 2019 8:20 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

I have seen issues where it causes a crash after about 3minutes.
Can you let me know the BeebSCSI board revision and firmware version you were running when you observed the crash?
by simoni
Fri Apr 26, 2019 11:33 am
Forum: hardware
Topic: Music 5000 clone in Kicad - Work in progress
Replies: 34
Views: 2204

Re: Music 5000 clone in Kicad - Work in progress

With the original spec 74LS ICs it's drawing about 400mA off the wall-wart, and the chips get quite warm. As an experiment I replaced about a dozen of the 74LS chips with 74HC equivalents I had in my parts store - and it appears to still function OK, but now draws about 300mA, and they don't get so...
by simoni
Wed Apr 17, 2019 7:46 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 114
Views: 7249

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 design...
by simoni
Wed Apr 17, 2019 5:33 pm
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 114
Views: 7249

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 wor...
by simoni
Tue Apr 16, 2019 7:13 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

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 point was really that there is a difference between the overall operation speed and the actual data transfer speed (the 'speed t...
by simoni
Tue Apr 16, 2019 3:53 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

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 'bum...
by simoni
Mon Apr 15, 2019 3:35 pm
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

If your code is repeatedly requesting a single 256 byte sector, it's going to be slow. It's also quite an unrealistic scenario since each read can pull back a couple of hundred sectors in a single call. You are basically driving the FAT stack in a manner which it isn't designed to be driven. It coul...
by simoni
Mon Apr 15, 2019 11:52 am
Forum: hardware
Topic: BeebSCSI 7_7
Replies: 161
Views: 7031

Re: BeebSCSI 7_7

The first issue is probably due to the file server making multiple requests or sub-dividing the SCSI requests in some way. The second could be anything, from a BeebSCSI issue to a bug in the file server (I would guess that the file server is sending a STOP command to the LUN - which would cause Beeb...
by simoni
Mon Apr 15, 2019 5:15 am
Forum: hardware
Topic: Raspberry Pi to 1MHz bus interface
Replies: 114
Views: 7249

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 bar...
by simoni
Sun Apr 14, 2019 6:02 pm
Forum: hardware
Topic: The sound of BBC graphics!
Replies: 12
Views: 762

Re: The sound of BBC graphics!

The BBC's sound circuitry consists of a SN76489AN (which generates the sound), an LM324 quad op-amp which filters and pre-amps and a LM386 which acts as a power amp and drives the speaker. There are basically three sources of noise and distortion: 1) the chips themselves - they are not 'pro-audio' a...
by simoni
Sat Apr 13, 2019 11:46 am
Forum: hardware
Topic: Master IO Controller IC15 - Databus pins?
Replies: 4
Views: 279

Re: Master IO Controller IC15 - Databus pins?

There are used to select between internal and external tube and 1MHz bus. ( fe34) Thanks! Makes a lot of sense :) &FE34 is the ACCCON register though... the documentation (Acorn engineering news 1) says that ACCCON is contained in the Memory Controller though (IC20): https://github.com/simoninns/Ac...