Plus colour monitor weirdness

[arnoldemu]

I was playing around with the Plus colour monitor, sending some values to the crtc to adjust vsync pos, vsync width, hsync pos, hsync width.
I'm doing this so I can check the response and then emulate this in Arnold.

Well I found that If I do this:

OUT &BC00,3:OUT &BD00,&38
OUT &BC00,3:OUT &BD00,&48

The screen seems to move very slightly by the size of a mode 2 pixel left and right.

can anyone else reproduce this on their Plus monitor or on a CPC monitor?

EDIT: Numbers should change vertical sync. Correct numbers added.#
EDIT: Markus tested it and use &88 instead of &48.

[Devilmarkus]

Here's my code:

Code Select Expand

10 OUT &BC00,3:OUT &BD00,&38
20 CALL &BB18
30 OUT &BC00,3:OUT &BD00,&88
40 CALL &BB18
50 GOTO 10

Results:
My CPC+ moved 1 pixel as Kevin mentioned.
My 464 (CRTC 1) and 6128 (Also CRTC 1): No rection
Emulators: (WinCPC, WinApe, JavaCPC) = 0 reaction, WinApe: Tried all available CRTC types
Edit: My 664 (CRTC 2): No reaction.

[redbox]

The screen seems to move very slightly by the size of a mode 2 pixel left and right.

Same on my 6128 Plus with colour monitor.

[Devilmarkus]

Could someone try that on a CRTC 0 - CPC?
AFAIK CRTC types 1 and 2 have fixed vsyncwidth.

[Bryce]

Maybe you might like to tell people how to find out which CRTC they have, as I would guess that most people don't know how to do this.

Bryce.

[arnoldemu]

Maybe you might like to tell people how to find out which CRTC they have, as I would guess that most people don't know how to do this.

Bryce.

Agreed.

Running a program is probably the best way but I don't have one ready yet.
I'll make one up using Offsets' CRTC test code.

The wiki gives the info about the crtc types from the markings on the chip.

http://www.cpcwiki.eu/index.php/CRTC

[CPCIak]

Here you are: I've got a basic routine which gives you the crtc type.

Code Select Expand

1 REM CRTC IDENDTIFICATION
2 REM BY Michael Kargas
5 MEMORY 16382
10 DIM c(111)
20 FOR i=1 TO 111:READ c(i):NEXT i
30 k=16384:FOR i=1 TO 111:POKE k,c(i):k=k+1:NEXT i
40 CALL &4000
50 a=PEEK(&3FFF)
60 PRINT:PRINT:PRINT "CRTC Type =";a
70 END
100 DATA 243,42,56,0,34,103,64,33,251,201,34,56,0,6,245,237,120,15,210,15,64,237,120,15,210,21,64,251,118,33,75,0,43,124,181,194,32,64,237,120,15,218,47,64,175,24,42,118,118,118,243,237,120,15,210,51,64,1,2,188,237,73,1,50,189,237,73,251
110 DATA 118,118,118,118,118,118,118,6,245,237,120,15,210,87,64,62,1,24,2,62,2,1,2,188,237,73,1,46,189,237,73,50,255,63,33,0,0,34,56,0,251,201,201