Search found 246 matches

by prime
Sun Aug 30, 2020 12:26 pm
Forum: Dragon Hardware
Topic: Quick & dirty test for new 63C09
Replies: 4
Views: 376

Re: Quick & dirty test for new 63C09

For what it's worth this is the code that the diag card uses to identify the 6309. ; ; Test to see if CPU is a 6809 or 6309. ; ; GetCPUType ; lbsr LCDClrScr ; clear LCD screen leax LCPUIs,pcr ; point to message lbsr DevWriteStr ; write it ldb #$ff ; setup b FCB $10 ; This will be CLRD on 6309, CLRA ...
by prime
Mon Jul 27, 2020 7:15 am
Forum: Dragon Hardware
Topic: Dragon memory map
Replies: 9
Views: 792

Re: Dragon memory map

CoCo 1 has 5V,12V *AND* -12V. Dragon has 12V and 5V CoCo 2,3 have only 5V. What is important though is the line that carries -12V on the CoCo1, carries +12V on the Dragon. Though unless you are using them they can be left unconnected. Certainly for a ROM cart you shouldn't need them. Cheers, Phill.
by prime
Thu Jun 18, 2020 12:02 am
Forum: Dragon Hardware
Topic: ?OM errors
Replies: 10
Views: 1218

Re: ?OM errors

A Dragon 32 board I thought was dead magically came back to life for as long as I held a probe to the RESET line on the CPU - turned out that pin was just not making a good connection in the socket! I had a problem almost identical to that on one of my Jupiter Ace boards except it was IIRC A8 of th...
by prime
Sun Jun 14, 2020 10:56 pm
Forum: Dragon Hardware
Topic: Dragon 32 PSU board picture, "48086?" "Issue 6?"
Replies: 4
Views: 595

Re: Dragon 32 PSU board picture, "48086?" "Issue 6?"

Reg3 looks like it has the insulation kit there, I think it consisted of a piece of mica? and an insert washer for the screw hole, along with some thermal paste (the white stuff round it).

Something like this : https://uk.rs-online.com/web/p/heatsink ... s/7128225/

Cheers.

Phill.
by prime
Sat May 23, 2020 10:46 pm
Forum: Dragon General
Topic: Comparison of Dragon mass storage options
Replies: 10
Views: 1669

Re: Comparison of Dragon mass storage options

robcfg wrote: Sat May 23, 2020 12:30 pm That's nice, thank you!

I'd add a Gotek floppy drive emulator to the list.
That's effectively what DragonDrive is isn't it? A DragonDOS cart with built in Gotek running flash floppy.

Cheers.

Phill.
by prime
Sat May 23, 2020 10:44 pm
Forum: Dragon Hardware
Topic: Adapting PC Joystick
Replies: 1
Views: 435

Re: Adapting PC Joystick

Yeah Dragon/Tandy and BBC analog joysticks do theings the correct way a potential divider, which is wy you never have to calibrate them because they are in effect self calibrating. However to read them you need to be able to read the voltage level which means some sort of DtoA and a comparitor. The ...
by prime
Fri May 22, 2020 12:51 pm
Forum: Dragon Hardware
Topic: Dragon 32 Power draw.....
Replies: 0
Views: 554

Dragon 32 Power draw.....

Posted this on the FB group but adding it here also as it may be useful.... Hi all, Some power draw measurements done on a Dragon 32 Board. Board 1, 16x4116 memory +12V draws 165mA +5V draws approx 660mA -5V draws approx 40mA Board 2, 8x4164 memory +12V draws 0mA unless a cartridge uses it.** +5 dra...
by prime
Wed May 13, 2020 2:37 pm
Forum: Dragon Hardware
Topic: Dragon 200 circuits and lower case mod circuits
Replies: 7
Views: 1007

Re: Dragon 200 circuits and lower case mod circuits

John W has also done a modern re-creation of the lower case board if you are on facebook, he posts regually there,

Cheers,

Phill.
by prime
Wed Apr 29, 2020 10:04 pm
Forum: Dragon General
Topic: Dragon power board problems!
Replies: 9
Views: 1650

Re: Dragon power board problems!

Regarding OS9 crashing, I'm not sure if this is relevant but stock OS9 doesn't boot on upgraded D32s because it expects the D64 serial port to be present at $ff04. On a D32, OS9 ends up writing to the low pia instead and freezes the machine during boot. I think the D32 64K upgrade guide describes h...
by prime
Wed Apr 22, 2020 1:26 pm
Forum: Dragon General
Topic: Debugging a real Dragon with NoICE - serial port
Replies: 7
Views: 2528

Re: Debugging a real Dragon with NoICE - serial port

I've used the Godil based emulator, and it is indeed excellent, being able to supend the CPU and look at registers / memory / single step is
indeeed useful.

There is anew version that has a proper level translator board and a cheapish FPGA development board.

Cheers.

Phill.