TMC PET48PN EISA+VL Motherboard 50 Mhz bus testing

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Re: TMC PET48PN EISA+VL Motherboard 50 Mhz bus testing

Postby Madowax » 2019-1-17 @ 10:32

feipoa wrote:I actually don't know anything about Amiga systems and have never owned one. So Amiga's use a DB9 connector for a bus mouse? That's interesting - I thought bus and inport mice were mini-DIN9.

Is there any hardware on your protocol converter board which needed to be altered to decrease the lag, or is the lag issue purely a software (firmware) alteration? If it is purely software, I wonder if you'd be able to send your firmware adapted for matze79's unit? Solving the lag issue with KVM's is of great interest to me, and I know others have commented as well that they KVM's showed horrific lag. Some KVM's seem to be OK though.

If shipping is not too costly, I might be willing to test your adapter directly. Do you have a spare, or just the single unit?

Has there been any thought to build a PS/2 mouse ISA card, as you have, but using a keyboard controller chip instead of doing a protocol conversion?


Basically I edited the firmware to remove the LEDs routine and to increase the MCU frequency from 8Mhz to 12Mhz, this change increases the speed ofc, but 12 Mhz is also evenly divisible by 1200 baud, in that way there is no serial speed margin of error like with a 8 Mhz frequency. These changes can also be applied to the original adapter, you simply have to change the crystal and his 2 ceramic caps and upload the new firmware in the ATTiny (1 programming fuse need to be changed in avrdude command line). The other difference is not applicable to the original adapter, infact being on the same pcb the attiny and the uart ic don't need any transceiver/receiver driver IC like the max232 and the counterpart IC you find on a PC serial interface to convert RS-232 signals to TTL-232 signals and viceversa, they communicate directly at TTL-232 level without any level conversion. I don't know if this will solve the problems related to the KVMs I have considered a PCB design with a PLCC-44 version of a PS/2 compatible KBC plus keyboard and mouse ports on the bracket, but this also needs modifications to the motherboard, like the bios modding and reflashing to enable the PS/2 mouse support and I suspect the removal of the original KBC IC if present or to disable the KBC if integrated in the chipset southbridge.
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Re: TMC PET48PN EISA+VL Motherboard 50 Mhz bus testing

Postby matze79 » 2019-2-22 @ 14:49

There is new Firmware, nice aproach i also had this idea :)
Now with higher Baudrate to reduce lag.

Where can i get a Card ? :D
https://dosreloaded.de - The German Retro DOS PC Community
https://www.retroianer.de
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Re: TMC PET48PN EISA+VL Motherboard 50 Mhz bus testing

Postby feipoa » 2019-2-22 @ 19:30

I think he said (in PM) that he's working on getting the final board ready. Will ship to me for KVM testing.
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Re: TMC PET48PN EISA+VL Motherboard 50 Mhz bus testing

Postby Madowax » 2019-2-22 @ 20:03

feipoa wrote:I think he said (in PM) that he's working on getting the final board ready. Will ship to me for KVM testing.

I'm working on it, but in the meantime I stumbled on an amiga 4000 motherboard and on a Octek Jaguar II, so you know... :lol:
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