(classic) New graphics option for the TRS80

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stefano
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(classic) New graphics option for the TRS80

Post by stefano »

Micro-Labs Grafix solution.
It took me a bit to setup the emulator and find the technical references, but after that it is probably the simplest graphics device to use in assembly machine code.
The new lib files are grafyx3.lib and grafyx4.lib, respectively for the Model III and Model 4. Basing on the documentation, the Model III is expected to have a reduced display resolution of 512x192 pixels where the Model 4 got 640x240, when not adjusted to be retro-compatible to Model III.
I couldn't reproduce such limit on the SDL2TRS emulator.
trs80-grafyx.png
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JenGun
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Re: (classic) New graphics option for the TRS80

Post by JenGun »

This is a bit confusing: even if the "microlabs" option is specified for TRS-80 Model III Grafyx, using I/O ports for graphics, the emulator falls back to the Radio Shack High-Resolution Board with 640x240 pixels: <http://www.trs-80.org/radio-shack-model ... ion-board/> ... the Model III Grafyx Solution used memory mapping: <http://www.trs-80.org/model-iii-grafyx-solution/>
stefano
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Re: (classic) New graphics option for the TRS80

Post by stefano »

Hmm, oddly I read a manual explaining that the same board could run in model 3 mode on model 4 but with lower rez. I supposed it was based on the same i/o ports trick.
Could it be yet another hw was produced by Micro-Labs ?
stefano
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Re: (classic) New graphics option for the TRS80

Post by stefano »

I found the answer:
The Model 3 Grafyx Solution has as its maximum resolution 512 x 192 dots
which can be overlayed with the standard text screen. The Model 4 version has
both an identical 512 x 192 mode for compatibility as well as the 640 x 240
mode. The Model 3 board is memory mapped while the Model 4 is port mapped.
Therefore, software written which directly accesses the hardware using OUT or
POKE statements will not transport from one board to the other without some
modifications. However, the Extended Graphics Basic offered on the Model 4 is a
superset of the Model 3 version for upward compatibility.
stefano
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Re: (classic) New graphics option for the TRS80

Post by stefano »

so:
The Grafyx Solution is controlled by data sent to port 131. There are
three basic modes of operation which are controlled by the two least significant
bits of the data written to this port: Normal, Hi-Resolution 640 x 240 (512 x
192 in the Model 3 mode) with text overlay, and Hi-Resolution 640 x 240 with
the text screen turned off.

...I'm going to rename grafyx3.lib to grafyx4_3.lib, this should limit the confusion and leave space for a future grafyx3 library
stefano
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Re: (classic) New graphics option for the TRS80

Post by stefano »

new lib names:

512x192, uTech board version 'model 4' installed on Model III, or Tandy HR board '26-1125'

-lgrafyx4_3


640x240, uTech board version 'model 4' installed on Model IV, or Tandy HR board '26-1126'

-lgrafyx4
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