Targa+ warning
4 messages in this thread
Just a note on an experience I have had with a Targa+/32. After a year
of successful operation sending 3DS/Targa+ output to video with a 386, I
decided to speed things up and obtained a Micron Technology 66 Mhz 486(VLB).
The Targa card in this computer appears to operate incorrectly. Under
3DS it renders to a NTSC monitor leaving broad horizontal bands of black and
thin horizontal bands of color.
However the card does appear to operate correctly when I run the Targa
demo to NTSC (TDEMO). It also works correctly when placed back in my old
computer.
After working over the phone with Truevision, they finally gave up and
felt that the computer has timing problems. We tried everything we could think
of-removing all cards but the Targa and the graphics card,config.sys and
autoexec.bat variations,operation with and without QEMM,checked for proper
settings for ADI drivers and 3ds.set- we even removed the local bus card
(viper) and used my old vga card instead(in an ISA slot of course). Everything
worked perfectly except the same problem with the 3DS/Targa rendering.
Has anyone else experienced a similar problem? Can there really be a
timing problem which specifically interferes with 3DS rendering?
In the meantime I'm back to slow motion.
-Mike
Yep, I've seen these funky color bands before. Try adding wait states in the
Targap.sys line.
I helped a friend set up a "name deleted" computer that required this due to a
"I/O no wait state problem".
Mike,
Either add wait states to the Targa+ (as Larry suggests) or check your
system BIOS CMOS settings for bus speed. You may be trying to drive the Targa+
too fast (compatible at 8-10MHz, sometimes faster, depending on machine). On a
66DX2, if bus is indicated as clock/divided by values, you may need to use by
8.
Kevin Krell – Computer Support Associates
Thanks for the comments. I have tried a number of combinations of wait
states without success. I will also try your suggestion of clock divided by 8.
The system board manual (Micronics) indicates that 1/4 should be selected for
my 66 Mhz DX-2. Do you know if using 1/8 will cause some kind of slow down?
I haven't tried it yet since I have moved the Targa+ back to my slow
machine and it is operating around the clock to produce a 3DS video of a
prototype manufacturing process.
Thanks again- Mike