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AndresNavarro82 / vt52-fpga

GNU General Public License v3.0
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very cool! #1

Open jhcloos opened 3 years ago

jhcloos commented 3 years ago

i saw your note to the tinyfpga list and started reading the code…

it might be interesting to implement the bell as a flashing led.

i do not recall wheter the vt52's bell supports varied frequency and/or duration, the led coulf light for however long a vt52 would have emitted audio.

or if not an onboard led, then perhaps voltage to an io pin...

AndresNavarro82 commented 3 years ago

Well, I haven't seen one in the flesh, but from what I've gathered the "bell" was actually produced by some kind of relay and the sound was quite unique. I think it also used a similar technique to simulate a "typewriter" sound when each key was pressed.

Here the bell could be implemented either via a short pulse or an oscillating value for a few ms. You could put either a led or one of those buzzers that are popular with Arduinos. The onboard led is currently assigned to follow the cursor blinking (only to have some indication of activity on the board) but could easily be reassigned in the pcf file.

As for the implementation, it should just be a matter of adding a case entry in command_handler.v, adding an output there and adding a buzzer module with the appropriate counter to turn off after a while (and oscillate if desired)

voronoipotato commented 3 years ago

I wonder how much more effort it would be to make this work over SSH. I've often thought it would be really cool to have a low power SSH only terminal. Normally I would have thought it kinda impossible but you've already done the whole terminal part :P. I was thinking maybe you could have a host that just SSH'es and communicates to the FPGA over serial.