Guru
Joined: 05/03/2018
Location: NetherlandsPosts: 5844
| Posted: 09:39am 05 Sep 2024 |
Hi Peter,
One "observation" on B5 for the 2040 VGA.
You mention the CPUSPEED can be set to 315MHz, to generate 75Hz VGA signal.
I tested this on the PETROBOTS, and it works. In MODE2 (320x240 16 colors) petrobots works very nice at 315MHz, I am not sure the video is 75Hz, but the monitor syncs, and gives good picture.
But...
The ROCKS (VegiPete asteriods imitation) uses MODE1 for video. When you run ROCKS, it totally locks up. PS2 keyboard unresponsive, serial USB unresponsive, black screen, but the monitor syncs, so video core is running.
rocks14.zip
When I repower, and put CPUSPEED back to 252000, Rocks works fine.
I do not issue this as a "bug" since the 2040 has always been 126/252MHz. The 315MHz was not used in any development before, since it was not available. But it is remarkable that mode2 works fine, and mode1 does not, since both use the same underlying 640x480 screen. And rocks14 does not use the tiles. It is fully BW.
Volhout
P.S. The 2350 is indeed faster that the 2040, the framerate from Petscii Robots goes from 60ms to 43ms average. Very nice.
Edit: rocks uses framebuffer f. Maybe, maybe that is the problem in mode 1
.
Edited 2024-09-06 03:40 by Volhout