Bizarre coding tricks

[Ray Norrish]

Just a curiouso, but I remember coding a LED trick that, using timers, made the LED fade out, rather than switch off. (This don't work in WinUAE )

I also made some code to do the same thing with the drive light, although people might not like it on real hardware, as this was a bit hectic on the drive motor.

Thing is, I also remember some coding trick where someone did a routine to play 1 channel music on the drive stepper motor.. anyone else remember this?

Today, I found out about the c64 demo where you have to "lick" the joystick port to activate some dubious animation.


Anyone know of any similar outlandish hardware coding tricks from the old days? Would be interesting!

[demoniac]

Years ago during a hardware, academic project, I inquired if there was a way to turn the Caps Lock LED on/off via software.

However, Andy Finkel had an interesting insight to the A1000 design...

The answer is no. The data link between the keyboard and the Amiga is
basically one way, keyboard to Amiga; while a bidirectional interface is
possible, it would have required using different parts for the communications
link. We (some of the software guys) wanted it back in the pre-A1000 days,
but we couldn't come up with enough justifications to overcome the cost
issues.

andy

Koljonen Kari-Pekka responded that...

Some years back inspired by Odyssey's caps lock flasher I decided to try
it out myself.

I don't remember the exact procedure very well, but it went something like
this (I used A500).

There is a direction flag in some cia register. Normally it states that
the keyboard is sending data. I switched this flag to the opposite
position and wrote the raw caps lock code to the keyboard data register
(was it $bfec01). The caps lock led turned on and after a while turned
off by itself.

Speaking of led flashing, a friend of mine did a power led/drive led
flasher (also years back with A500) with lot's of different shades of
red/green/whatever color the leds were.

--
/K-P Koljonen -- Hippopotamus Design

I don't exactly remember why I wanted to do that w/ the Caps Lock LED in the first place...

I think it was to going to be used for identicating when my homebrewed freezer device was ready.

[mr_0rga5m]

Originally Posted by Ray Norrish

Thing is, I also remember some coding trick where someone did a routine to play 1 channel music on the drive stepper motor.. anyone else remember this?

Yea .. i remember these .. (even mentioned it here & here before) .. cool routines .. ingenious tricks

i'm sure there was more tunes than daisy daisy tho ...

Again with the LEDs i remember it happening quite a lot on the C64 .. Drive LEDs pulsing along to demos tracks etc.. But i dont remember seeing it on the Amiga ? ... (Unless i did but just thought crap ive seen this on a c64 years back )

[bobbybearing]

yes, fade LED is cool, but work fine only on A500
(see Silents Demon Download boot)

fadeledOff
move.w #300,d2
move.w #0,d3
move.w #1,d1
bra.s fade

fadeledOn
move.w #0,d2
move.w #300,d3
move.w #-1,d1

fade
move.w d2,d0
bmi.s end
.loopoff
bclr #1,$bfe001
dbf d0,.loopoff

move.w d3,d0
bmi.s end
.loopon
bset #1,$bfe001
dbf d0,.loopon

add.w d1,d3
sub.w d1,d2
bra.s loop
end rts

the Caps Lock Led crash on A1200 ! (see Alcratraz Odyssey)

for a music with drive motor, it's "GuruMusic" (see this post)

[Steve]

Originally Posted by Ray Norrish

Just a curiouso, but I remember coding a LED trick that, using timers, made the LED fade out, rather than switch off.

The LED flasing trick can be coded by using bit 1 of the CIA register.
Check out this thread: http://eab.abime.net/showthread.php?t=9950

[Galahad/FLT]

Spook of Digital used the CAPS Lock led trick on The Punisher demo, alas because of this, it crashed on A12oo's.

I do remember some buffoon magazine reviewer commenting on piracy, and how all cracked games had viruses, and that sometimes the 'stupid' crackers would 'screw around' with the Power LED whilst a game was decrunching, and they were clearly 'banging the hardware'! Dullard... it was also the Audio filter!

[Photon]

Originally Posted by Ray Norrish

Just a curiouso, but I remember coding a LED trick that, using timers, made the LED fade out, rather than switch off. (This don't work in WinUAE )

I believe the demo group Powerdrive was the first to fade LEDs on Amiga (A500). It would have been around '89-'90.