Search found 12 matches

by lee
Wed Dec 19, 2012 12:01 am
Forum: Operating system
Topic: EhBASIC update
Replies: 5
Views: 20312

Re: EhBASIC update

Well the number of errors matches but the line numbers are off by 201, however it looks like unix68k doesn't support any sort of conditional assembly so .. If you want nonexistant variables to return zero or a null string comment out all the code in these blocks. ifeq novar . . . endc Or if you want...
by lee
Mon Dec 17, 2012 6:45 am
Forum: Operating system
Topic: EhBASIC update
Replies: 5
Views: 20312

Re: EhBASIC update

I should adapt the new version to Kiwi. Yes you should, there are quite a few improvements. 8^)= The number to string routine has been modified to output up to seven significant figures, IF..THEN statements can now have an ELSE section, there is a new USING$() function for formating number output a...
by lee
Sat Dec 15, 2012 1:31 pm
Forum: Operating system
Topic: EhBASIC update
Replies: 5
Views: 20312

EhBASIC update

Three small updates to EhBASIC fix UCASE$(), LCASE$() and USING$(). See here for details.

The version is now 3.52

Lee.
by lee
Wed Oct 24, 2012 6:02 pm
Forum: Hardware
Topic: Power supply
Replies: 18
Views: 53800

Re: Power supply

Maybe re-arrange parts and move all analog parts nearer towards the power plug/switch to keep these traces short. Actually no, the opposite would be better. Move the analog sections to the other end of the board and have only two points where the analog supply rails meet the rest of the board. If I...
by lee
Mon Oct 22, 2012 6:55 pm
Forum: Hardware
Topic: Power supply
Replies: 18
Views: 53800

Re: Power supply

You mean the SID and the output followers should be powered with the same source? Yes. When you go to the trouble of making a quiet supply rail it should be used for all the downstream analog stages. It will probably help if you avoid digital signals in the 0V path as well. Anyway the disturbance c...
by lee
Mon Oct 22, 2012 12:48 am
Forum: Hardware
Topic: Power supply
Replies: 18
Views: 53800

Re: Power supply

The 9V supply for the SIDs is linear regulated already. But I assume the noise comes from the power supply The audio output followers are powered by the +12V rail, they should be powered by the SID +9V. Also the +9V could probably do with some more decoupling, say a 100uF to 470uF, low ESR electrol...
by lee
Sat Oct 20, 2012 4:35 pm
Forum: Hardware
Topic: New hardware revision?
Replies: 95
Views: 263682

Re: New hardware revision?

The ATMega8 is only used to avoid bit banging of the two PS/2 ports not for accessing SD cards.

Did you follow the link?

Lee.
by lee
Thu Oct 18, 2012 8:38 pm
Forum: Hardware
Topic: Power supply
Replies: 18
Views: 53800

Re: Power supply

I fear a pontential ripple noise disturbing audio and video signals.

A lot of motherboards have linear regulated supplies just for their audio chip analog voltages. I just looked at five boards from the top of my pile of boards and three have regulators and all have local supply filtering.

Lee.
by lee
Thu Oct 18, 2012 8:28 pm
Forum: Hardware
Topic: New hardware revision?
Replies: 95
Views: 263682

Re: New hardware revision?

SD cards ... What communication protocol do they use? Ok, perhaps you should keep the ATMega8 . Well, the main reason for the 68008 was the simplified PCB layout. Only a half or quarter of data lines have to be routed. The 68030 can also operate with only an 8 bit bus, so you can boot from a single ...
by lee
Wed Oct 17, 2012 9:20 pm
Forum: Hardware
Topic: New hardware revision?
Replies: 95
Views: 263682

Re: New hardware revision?

Other suggestions.

Drop the floppy, SD card support would be more usefull.

Replace the EPROM with FLASH.

Interface the keyboard/mouse directly, not too hard to do.

ISA bus slots for all my classic ISA CPU cards so I finally have a home for things like this.

Lee.