urban soul

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About urban soul

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    MIDIbox Newbie
  • Birthday 01/01/1970

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  • Website URL http://www.schlemmer.gmxhome.de

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  1. chaining 8x HC595

    These are no dirty words. You hear them a lot from kids. Assh*le {:-)?Any other ideas? Now that I got to know the jokemaster of the board a little bit better, how about the other {counter} members ?  Is there anybody who can compete with you, stryd_one ? This 'I-am-who-I-am' statement is honest. I like that one. That's an important point. Probabely the best place to start off, for anybody.
  2. chaining 8x HC595

    Arrrgh, your telling jokes that are most likely understood by people which got to know you better... That's rude, BTW :-) If I can laugh my ass off while reading your posts, we'll have a good time. You can be rude. Thats ok. As long as you stay funny.
  3. chaining 8x HC595

    Let forum member doc explain by himself if he feels offended by the sentense: 'May I ask you to give at least one reference' .  (was up for about 30sec.) I have never seen a moderator getting into personal flams with newbies. Normally moderators are too busy. Nobody ask you to post OT nonsense like 'secrets' we share. Do you think this is the job of a moderator? If someone throws a stone I have to react. You are the aggressor here. Did I prove your pov again ? Not so difficult. It's a self fufilling prophecy.
  4. chaining 8x HC595

    rudely ? No. plain wrong. bye
  5. chaining 8x HC595

    I didn't know that editing topics is forbidden in here. For the record - I asked doc kindly to give a referemce. There's no secret. I then decided to search the forum on my own. Is there anything wrong with it? @cimo: a can send you the script which turns LateX into a blog. Just send me a email.
  6. chaining 8x HC595

    Thanks for that info. Would be nice. Most likely its bad soldiers. Have to look at it with an osci.
  7. chaining 8x HC595

    Probably not many people have more than 64 LEDs to control. I dont know. Also in my case I soldered one point in less than one second... bad habit.
  8. chaining 8x HC595

    @Sasha well I have no solution other than mounting all 16 HC595 on one single PCB in your case. In theory the digital clock signal looks like a pulse wave. A cable has a capacity and also a resistance and acts therefor as lowpass filter. Result: the edges of the clock signal are smeared. For the most important capacity the surface of the cable plays a major role. Ultrathin copper cables should be best suited. (0.1mm) You can determine the quality of the clock signal with an osci. Also in theory cable length of less than one meter should be non-critical. (Just a quick guess, I can do the math if you ask me) In practice every soldering point is disturbing too. If the HC595 does not terminate the clock signal correctly (this is very unlikely) reflexions may also occur. The longer the chain the more likely it is that an error in reading the clock signal occurs. When you touch certain points with your fingertips you change this very unstable reading state.
  9. chaining 8x HC595

    Now - I did additional testing and capacities seem to be very important for this chaining of serial ports. It is not only the bypass caps it is the connection from one serial out to the next serial in. I soldered the additional bypass caps but that didn't change too much. Then I checked the ground connection if each HC595 and that did improves some things. Still it is sort of unstable - when I touch certain points with my fingertips other LEDs are lit... Finally - after having a closer look at the design - it was pure nonsense to mount the HC's freely spaced somewhere on the front panel. Maybe it is best if I redo the whole DOUT stuff on a proper smashtv PCB. Thats because the frequencies involved are critical to wiring.
  10. chaining 8x HC595

    No, typo is on your side here... 4x 100nF I have soldiered, additional 100uF per DOUT PCP I left away. I'm on a standart PCB v.3 with PIC18F452, OS is MB64. Coming back soon with more test results, thx for the replies.
  11. chaining 8x HC595

    I need the opinion of some experienced developers... I have connected 64 LEDs to 8 74HC595 according to mbhp_doutx4.pdf. Observation: - Everything works fine - if I 'ping' (note on followed by note-off) each led. - However if leds are lit, leds 32...63 show random behaviour, even flickering occurs. In this case also leds 0...31 are triggered randomly. Design notes: - Did not use PCB, wired free - left away the two 100uF caps - LEDs have 1k resistors (instead of 220R) ------------- I looked at the datasheet of the HC595 and saw that it operates quite at high frequencies (serial 100MHz typically). Therefore the 100uF may be important. (I'm on the way to buying them now). But I got a strange feeling that this is not all about it. I wonder if termination of the bus is required. Any help greatly appreciated. Urban
  12. 32 switches + leds = current ?

    Hi, thanks for the reply. I had a look at the specs of HC74 and I have the same findings. Also the inputs of the HC74 draw enough (<4mA) current to have the LEDs glim. Thanks again for diving into my question. I think your option 2 is the best way to do it! Urban
  13. 32 switches + leds = current ?

    Hello, I am new on the list. My MidiBox is here: http://www.schlemmer.gmxhome.de/ -> Galery My design is strictly one-way. No feedback from the DAW. Is it a good idea to replace the 10k resistors on the DIN module with 220R ones so as to drive 32 LEDs by the buttons ? Vss---220R---LED---BUTTON---GND The 220R resistor would be connected to DINx4. But then pressed button gives +1,6V instead of 0V. Does the 74HC165 draw any current here? Or is it possible to connect after the LED ? Lot's of questions. Thanks TK  - this is an amazing project! Urban