Search found 1394 matches

by pser1
Sat Jan 09, 2021 8:01 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

we are happy enough to have a hardware guru like Darren Atkinson helping us to solve awkward problems Thanks a lot, Darren, you are vey kind!! cheers By the way, I could not resist and have taken two resistor arrays of 4k7 and a std resistor 5k6 .. the only components I have right now and have added...
by pser1
Thu Jan 07, 2021 6:21 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

Hello John, sorry for the delay, but it has been impossible to take the photos earlier ... I attach here the eight images we use for testing and I can asure you that vertical bars do *not* appear on the screen on any of them. But taking a photo opens a door for camera-screen effects and you will not...
by pser1
Wed Jan 06, 2021 12:49 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

Hi John,
most probably I will not have the time untill late evening ...
But then I will take some photos of a few images in this resolution
BASI12 is using YJK color mode that allows for 19268 colours on screen
with 256x424 pixels resolution
cheers!
pere
by pser1
Tue Jan 05, 2021 11:42 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

Hello John, this is strange, I have not this problem. What mode where you looking at? Let me know and I will try it tomorrow... The best images use to be for BASI12 which uses two frames for each image. But the other resolutions give very acceptable images too and no vertical noise bars at all ... c...
by pser1
Sun Jan 03, 2021 11:03 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

hello, just to give a little hope to Dragon-MSX2+ users ... Mike Miller has found that the SDC firmware activates FIRQ for next byte very fast (10usec) and he would like to have the chance to double this value just to see what it happens ... So, I have contacted Darren Atkinson telling him Mike's id...
by pser1
Sun Jan 03, 2021 6:32 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

oops, I have tried to start the Dragon with the MSX2+ board connected but without power supply ... The Dragon goes mad and fills the screen with garbage. No way to start in this setup, so the pins from the MSX2+ module without power supply do not have the expected level and are pulling to the wrong ...
by pser1
Sun Jan 03, 2021 6:27 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

Hello, I have done a first try changing the DP50E read sector routine, I have tried copying the ROM to RAM and then inverted the lda and ldb to acknoledge the interrupt first place. I have changed the cmpx to three nops and then modified the branch to be a BRA But loading a program to play some VGM ...
by pser1
Sat Jan 02, 2021 8:35 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

Hi Stew, I hope some of these questions will be answered by John I just wanted to say that the oojamaflip (Y-cable type module) has *NO* power supply So the CoCo-SDC gets the power from the expansion bus but the MSX2+ board is powered individually to avoid problems with the D64 power supply. cheers ...
by pser1
Wed Dec 30, 2020 8:22 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

in fact the Dragon-MMC emulates both the Dragon-DOS and Extended Basic if I remember correctly It seems to be a DDOS1.0 derivative, but there must be some changes (hard/soft) that make it behave in a different way than the strandard DOS1.x do When we start one of these from an SDC bank, problems kee...
by pser1
Wed Dec 30, 2020 6:13 pm
Forum: Dragon Hardware
Topic: Problems with DOS using an Y-type connection
Replies: 41
Views: 1475

Re: Problems with DOS using an Y-type connection

Hi Stew,
I forgot to answer your question about interrupts ...
The V9958 sends an interrupt every frame (/FS) to the computer via the NMI pin
We know that this could produce abnormal read/write results as this interrupt is
the one that ends the reading loop (that uses FIRQ)
regards