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McTrinsic

Posted Fri Apr 24, 2020 11:59 am

Doesn’t work, tried that :).

An example: the driver for the Melody 1200 checks for the pcmcia device in RAM. Unfortunately, that is only in RAM if there is the respective hardware...

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Harjit

Posted Sun May 10, 2020 9:09 am

Back in 1986/1987, my friend, Jim Rothrock and I made a battery backed up real time clock called LittleBen which plugged into the second mouse port.

Jim wrote the software and I designed and built the hardware. I think we sold about 30 of them. They were all hand built. It was my first experience in running a business - IIRC, we broke even on the hardware but didn't make enough money to pay Jim for writing the software. I designed the circuit, printed circuit board, had them manufactured, called around and got quotes for all the parts, ordered the "best deal" - back then shipping was like $2.xx for a package! Then, I hand assembled them. This was the most challenging part because it was a lot of soldering and doing it at home without a great workbench was difficult. Then, I had to let them run for a little bit so that I could fine tune the frequency so that they didn't gain or lose time, make sure the battery was charging and holding charge, etc.

I did the hardware development on an Atari 800 using Action! (https://en.wikipedia.org/wiki/Action!_( ... _language)) since I was more familiar with that setup than my Amiga. Jim looked at it and ignored it and wrote his own version.

Inside, it had a Signetics chip (now NXP), a NiCd battery which was charged from the port, a variable capacitor to trim the frequency and a couple of other resistors, capacitors and I think a diode (for charging).

I've attached a picture of the manual, hardware unit, and the chips that were in it.
Attachments
LittleBen.jpg

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Christian

Posted Mon May 11, 2020 9:16 pm

Thanks for sharing. You used the same RTC chip that Microbotics used in the Stardrive and Multifunction Modules for the Starboard 2.
Maybe also in the MouseTime.
I hadn’t seen that chip being used much, but then again the Oki and Ricoh Chips used with the later Amiga models are probably also not that common.





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