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Olytext 20 and 30 #113601
06/22/18 07:15 PM
06/22/18 07:15 PM
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rfka01 Offline OP
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rfka01  Offline OP
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Picking up from the "New Dumps" thread ...

Thanks to Robbbert - he created a skeleton driver for the Olytext 20.

I'll contribute what I can, but it would be really great if some of the devs could chime in.

The NS405 Terminal Management Processor in the Olytext 20 is also used in the Atari XEP80 interface module that produces 80x25 text.
The XEP80 is emulated in the Altirra emulator, but I can't judge whether this is license (GPL2) or code compatible and could be included into MAME.

Here's a data sheet for the NS405.


NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
Re: Olytext 20 and 30 [Re: rfka01] #113602
06/22/18 08:17 PM
06/22/18 08:17 PM
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Just Desserts Offline
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GPLv2 is compatible with MAME, unless I am greatly mistaken. As far as code compatibility, it's likely not at all. Different emulators, different frameworks.

Re: Olytext 20 and 30 [Re: rfka01] #113603
06/22/18 10:07 PM
06/22/18 10:07 PM
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R. Belmont Offline
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Yeah, video chips in particular are probably better off just rewritten from the manual.

Re: Olytext 20 and 30 [Re: rfka01] #113604
06/23/18 01:38 AM
06/23/18 01:38 AM
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Robbbert Offline
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It's not just a video chip - it's a cpu, crtc, dmac, serial & parallel interface, and more, all rolled into one.

The rom that was dumped isn't a character generator - it's the firmware. The character generator is internal.

Re: Olytext 20 and 30 [Re: rfka01] #113606
06/23/18 10:07 AM
06/23/18 10:07 AM
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rfka01 Offline OP
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I've made a comparison of the opcodes of the 8048 vs. NS405 (based on the names in mcs48.cpp and the NS405 datasheet).

You can find the table here.

I've marked where opcodes are shifted to different positions, have names similar enough to be the same and have identified a possible mislabeling.

In MAME, 8048 has the following commands vs. NS405
Code
80	movx_a_xr0	MOVX @R0,A
81	movx_a_xr1	MOVX @R1,A


Later this is just the other way round
Code
90	movx_xr0_a	MOVX A,@R0
91	movx_xr1_a	MOVX A,@R1


Of course it's possible the NS405 just swapped these opcodes, but maybe this is worth a check by someone who knows their way around the 8048 core if MAME has just assigned the wrong labels to the opcodes at the right place or if the opcodes in mcs48.cpp are actually swapped.

Last edited by rfka01; 06/23/18 10:09 AM.

NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20
Re: Olytext 20 and 30 [Re: rfka01] #113607
06/23/18 11:57 AM
06/23/18 11:57 AM
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R. Belmont Offline
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ETA: The instructions in MAME are correct for the MCS-48 series; the NS405 appears to have those instructions reversed.

Last edited by R. Belmont; 06/23/18 12:16 PM.
Re: Olytext 20 and 30 [Re: rfka01] #113608
06/23/18 01:09 PM
06/23/18 01:09 PM
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AJR Online content
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MOVX also happens to do a 16-bit transfer on the NS405, so it's not quite the same instruction even if it's written the same way.

Re: Olytext 20 and 30 [Re: rfka01] #113618
06/28/18 10:49 AM
06/28/18 10:49 AM
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rfka01 Offline OP
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For Wordstar, the Televideo 950 screen setting works best.

[Linked Image]


NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20

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