Worth a visit

[Shiv Mathur]

Since it's been so quiet here lately, here's something
quite different and quite remarkable:

http://www.youtube.com/watch?v=XKRj-T4l-e8

Hoppie, you play this, right ?

Cheers,
Shiv

[frumpy]

Or the same thing for computer geeks *g*

http://www.youtube.com/watch?v=qK0JkvTCp9Q

[Jeroen Hoppenbrouwers]

Ok I admit "guilty".

Back at university around 1987, I enrolled in a microcomputer architecture course at a more advanced level, i.e., working with actual hardware, an 8085 on a breadboard setup. At that time, I had already been programming Z80 chips in machine language for years at home and had completed some major projects. But no formal credits, so here I went.

Since I came from a weird faculty ("Philosophy and Social Sciences", really), nobody from the hard core nerds from Electro and Maths wanted to team up with me. Ok. No problem    

First task, which I had seen in the course guide, was to get the 8085 to produce a "buzzzz" using a one-bit speaker. There was no real timer, just a 1 MHz clock cycle and the cycle count table per instruction. So, I decided to bluff my way through. At home I calculated the A 440 base loop, and then stupidly set up a table with notes and lengths, which was run over by a simple sequencer that played all notes one by one. As easy as it sounds, and actually not a problem at all in 8085 assembler. I wrote down the hex codes on a piece of paper and biked to the university for the first course.



While the others were still hopelessly lost in getting the monitor program (16 keys, four 7-segment displays, a bit like the attached picture) to run and produce their first assembly program that did not reset the board, I quietly punched in the hundred or so hex codes. I even took the time to review them. By the time the first people started asking the assistants for help, I hit RUN and leaned back.

BVW565 buzzed through the room, about the first 10 bars of the Fuga, and not polyphone. But the effect was rather remarkable    :twisted:

I got signed off and left that session within 20 minutes, leaving some nerds sort of desperate what kind of philosopher I was    :mrgreen:


Jeroen

PS. There was one other outsider, from the faculty of "Architecture, Building and Planning", who probably had misunderstood the name of the course for "computer-aided architecture."

[Jeroen Hoppenbrouwers]

There's an awful lot of music being made by ancient equipment. Some brilliant.

http://www.youtube.com/watch?v=Ht96HJ01SE4

[frumpy]

Sometimes I try assembler too. Its with Atmel chips,
cheap 8-bit RISCs with ADC and PWM channels. The
whole usb-programmable board cost 15€. Tried the
440 Hz (seems to be a standard tutoring program *g*)
with the internal timer, it fires an interrupt every 1/880 s
to change the controlbit for the speaker.
These days I am trying to program an RPM indicator just
by using the cycle-counts as a timer and a 16-bit counter
to count possible ignitions. Once there is a real ignition
registered, I try to swap the bits in the 16bit counter to
have a measure for the RPM (a lot of counts in the 16bit
means a lot of time went by, therefore low RPM). Lets see
how it will work out