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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 10th Apr 2024, 7:21 pm   #1
Nick_B333
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Default More INS8073

I see the last time this device was mentioned was back in 2022 so I though I'd share my recent fun and games. I picked up three INS8073s a while back, still have two of them. I had some boards made up from a design I found online and with some modifications to the circuit I have it up and running. Apart from Phil_G's PICL I've not done much with earlier SC/MP stuff but looking at recent developments here the instruction set seems to be quite different.

NIBL tiny BASIC is located on the chip from 0x0000 to 0x09FF. I've added 32k RAM from 0x0000 to 0x7FFF. The original design had 2k from 0x1000 to 0x17FF and I was concerned that it might cause issues where it overlaps with the BASIC rom area but in practice there doesn't seem to be any problem. I've also added the Universal Monitor at 0x8800 which can be called by LINK #8800. This can Load and Punch both intel and motorola hex files.

I can create programs in different areas of RAM and switch between them with NEW#1100, NEW#2000,... but one of the 8073s seems to have an address fault as PRINT TOP returns 0 at NEW #4000.

There doesn't seem to be much going on out there with the 8073 but I have noticed one Japanese blogger who's developing an 8070 project.
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Old 10th Apr 2024, 7:50 pm   #2
Mark1960
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Default Re: More INS8073

The 8070 instruction set is very different to the 8060.

On the 8073 any access to addresses for internal rom or ram does not generate an external memory access.

Unfortunately there seems to be no way to disable internal rom, so not so easy to replace the internal rom with something else, unlike the intel mcs48 series that support external memory for development.
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Old 10th Apr 2024, 8:13 pm   #3
Nick_B333
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Default Re: More INS8073

Quote:
Originally Posted by Mark1960 View Post
Unfortunately there seems to be no way to disable internal rom, so not so easy to replace the internal rom with something else, unlike the intel mcs48 series that support external memory for development.
Hi Mark, I've considered one workaround - 8073 should auto-run a BASIC program in ROM at 0x8000. A one-liner pointing to the start of a machine code routine something like
Code:
1 LINK #8100
might work. I want a nice sign-on message rather than > which should be possible with the auto-run.
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Old 10th Apr 2024, 9:54 pm   #4
Mark1960
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Default Re: More INS8073

Hi Nick, its also possible to redirect the input/output routines, so it would be possible to modify the output routine to run some other software. It doesn’t seem possible to change the interupt vectors, but maybe I just didn’t find the info on that yet.
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