[comp.sys.amiga.hardware] update of the screen

jms@tardis.Tymnet.COM (Joe Smith) (01/05/91)

In article <1990Dec14.035928.26869@lingua.cltr.uq.OZ.AU> colin@lingua.cltr.uq.OZ.AU (Colin Canfield) writes:
>	Do the new ecs modes update the screen at higher number of frames/sec
>or is it still 60?

The PREFS programs that come with the A3000 allows you to change the
Workbench screen to use many of the new modes that the ECS provide.  [The
following list does not include any of the Lores modes (32, 64, or 4096
colors) because 320x200 or 320x400 are not optios for the Workbench screen.]

The old modes for Workbench:
  NTSC:Hires            = 640x200, up to 16 colors, no flicker, 15KHz & 60Hz
  NTSC:Hires-Interlaced = 640x400, up to 16 colors, flickers,   15KHz & 30Hz
   PAL:Hires            = 640x256, up to 16 colors, no flicker, 15Khz & 50Hz
   PAL:Hires-Interlaced = 640x256, up to 16 colors, flickers,   15Khz & 25Hz
New features: Can switch between NTSC and PAL on the fly.  With a VGA or
multi-sync monitor connected to the 15-pin connector on an A3000 or the
A2320 Display Enhancer, the interlaced modes do not flicker.  (31KHz mode.)

Semi-new modes for Workbench:
  A2024_10Hz: = 1008x1024, 4 shades of gray, same CHIP bandwidth as 640x400x8
  A2024_15Hz: = 1008x1024, 4 shades of gray, same CHIP bandwidth as 640x400x16
These only work on the Hedley A2024 monitor.  They do not require the Enhanced
Chip Set, just new software (a new version of graphics.library).

The new modes for NTSC or PAL monitors (or genlocks):
  NTSC:SuperHires      = 1280x200, 4 colors out of 64, no flicker, 15KHz & 60Hz
  NTSC:SuperHiresLaced = 1280x400, 4 colors out of 64, flickers,   15KHz & 30Hz
   PAL:SuperHires      = 1280x256, 4 colors out of 64, no flicker, 15Khz & 50Hz
   PAL:SuperHiresLaced = 1280x256, 4 colors out of 64, flickers,   15Khz & 25Hz
These 4 modes are great for video titling.  The Display Enhancer has to be
bypassed, since it is designed to handle 140 nanosecond pixels (320 wide) or
70 nanosecond pixels (640 wide), but not 35 nanosecond pixels (1280 wide).

New modes for VGA or multi-sync monitors:
  Productivity:        =  640x480, 4 colors out of 64, no flicker, 31Khz & 60Hz
  Productivity-Laced:  =  640x960, 4 colors out of 64, flickers,   31Khz & 30Hz
The Display Enhancer automatically switches itself out of the way when these
modes are selected, and lets the VGA-compatible monitor handle the signals
directly.  These modes cannot be used with genlocks.

>	If it is still 60 is there any way of making it faster, preferably
>~8 ms between screen updates (twice the current) ?
>			colin@lingua.cltr.uq.oz.au

The horizontal frequency, vertical frequency, duration of HSYNC and VSYNC are
all programable with ECS.  I suppose it's possible to set them for 640x240
with 4 colors at 31Khz and 120Hz, but that's not a standard combination for
VGA or multi-sync monitors.  It's not one of the supported display modes.
-- 
Joe Smith (408)922-6220 | SMTP: jms@tardis.tymnet.com or jms@gemini.tymnet.com
BT Tymnet Tech Services | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms
PO Box 49019, MS-C51    | BIX: smithjoe | CA license plate: "POPJ P," (PDP-10)
San Jose, CA 95161-9019 | humorous dislaimer: "My Amiga 3000 speaks for me."