I made my own interface card!

Schlowski · Post by **Schlowski** » Wed Sep 21, 2005 9:05 am

lol, now we can call him VicGyver (spelling?)

vic user · Post by **vic user** » Wed Sep 21, 2005 9:52 am

sounds good to me!

chris

6502dude · Post by **6502dude** » Wed Sep 21, 2005 12:19 pm

vic user wrote:do you still have the programs for your projects?

chris

Unfortunately, most programs I wrote for Vic-20 hardware projects that I did in the 1980s were cassette based and they have been lost or damaged over the years.

I few things I burned to eproms, but I have erased and reused most of these.

User port control routines are usually pretty short anyway and easy to write.

vic user · Post by **vic user** » Wed Sep 21, 2005 12:48 pm

User port control routines are usually pretty short anyway and easy to write.

it looks like you just have to deal with two memory locations, which is nice.

tonight i hope to set up on my breadboard a LED circuit using a transistor as the switch.

if it works ok, then off to use an i/o line from the vic to feed that base current, and hope the LED comes on!

chris

6502dude · Post by **6502dude** » Wed Sep 21, 2005 1:08 pm

Dont forget current limiting resistor from user port to base of transistor and a current limiting resistor for the LED.

If you have MOC3020 chip handy you can connect this to user port and switch 120vac loads up to 100ma. This is a really cheap way use computer control of 60watt lamp without clunky relays.

Connect a triac to output of MOC3020 and you can handle AC loads of several amps.

If you are not used to working with AC line voltage ........ be careful

vic user · Post by **vic user** » Wed Sep 21, 2005 6:00 pm

9 volts DC and low current is about all i can handle i think.

Dont forget current limiting resistor from user port to base of transistor and a current limiting resistor for the LED.

resistors are my friends, as far as i have been told in many books, but my best friend is ground

chris

Post by **Jeff-20** » Wed Sep 21, 2005 6:53 pm

(still laughing from the McGyver pic -- perfect timing).

vic user · Post by **vic user** » Thu Sep 22, 2005 9:21 am

Does this look right to be able to turn on/off the LED from an I/O line on the vic?

+ 5 volts------------------------resistor----------LED-----collector

I/O line--------------------------resistor----------base

emitter----------------GND

here is a better representation:

http://web.ncf.ca/ex809/circuit.bmp

thanks in advance for any replies.

chris

6502dude · Post by **6502dude** » Thu Sep 22, 2005 10:43 am

Nice picture.

This should work fine.

Suggested resistor values are 330 or 470 ohm for led resistor and 1K ohm for I/O line to base.

vic user · Post by **vic user** » Thu Sep 22, 2005 10:56 am

thanks for the resistor advice!

oh man, this is going to be neat if it works!

chris

vic user · Post by **vic user** » Fri Sep 23, 2005 9:10 am

well i hooked up the circuit last night, and the transistor works, but i am going to have to get a multimeter tonight.

i can get the LED to light up, no matter which I/O line i use to plug into the base, and can even get it to light up just by holding the wire with my fingers!

i then replaced the +5 volts line with an I/O line to power the circuit, and although the LED was faint, i did get a closed circuit.

poking the particular I/O line did not seem to affect the power level either.

i picked I/O line 8 (PB7?) so its decimal value is 32, yet no effect.

chris

Schema · Post by **Schema** » Fri Sep 23, 2005 10:38 am

Did you set the user port to "all outputs" first?

vic user · Post by **vic user** » Fri Sep 23, 2005 11:01 am

i set only the last I/O line to output, (decimal 32) and also did try to set them all to output (decimal 255), but no dice.

the multimeter should figure out what the heck is going on or not on

chris

vic user · Post by **vic user** » Fri Sep 23, 2005 3:31 pm

i feel so silly.

once i used the proper value for 2^7 i got it to work

although i can turn on/off an LED just using an I/O line for power, i can see why using a transistor makes sense.

i am now having fun getting two LED's to blink at different rates etc..

i should have bought more transistors

chris

p.s. i want to thank everyone who has helped me get to this point. i am having a huge blast interfacing the breadboard to the vic!

vic user · Post by **vic user** » Sun Sep 25, 2005 4:28 pm

i'll be picking up more transistors tomorrow during lunch break, but right now i have 4 LED's hooked up and wrote a little program that takes a random value from 0 to 255 and pokes the value into a sound register as well as to the I/O ports, (then a random delay loop) so I get a crazy sound and light show

one thing i noticed, is how much faster the program is when i poked a variable having the value 37136, rather than using 37136 directly, for example.

chris