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PWM controlls, best chip for several at once? AVR or PIC

Discussion in 'Microcontrollers' started by Triode, May 3, 2009.

  1. dougy83

    dougy83 Well-Known Member

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    Static LCDs are supposed to driven with AC; for a segment to be on, the signal on its pin will be having opposite polarity to the respective common pin, or a segment to be off, the signal on its pin will be the same as the backplane/common. Attempting to drive segments with DC will degrade the LCD.

    A couple of links that may help:
    Static Driven LCD Technology
    Driving static LCD displays | Micro Basics
    Using the DS89C450 as a static LCD display controller
     
  2. Sceadwian

    Sceadwian Banned

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    Look like a real pain to drive directly. Especially if it's multiplexed display.
     
    Last edited: May 11, 2009
  3. dougy83

    dougy83 Well-Known Member

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    No doubt it's more effort than required, a simple serial interface to a PC would be better for debugging.

    I don't think the one he showed is multiplexed - due to the large number of pins and only 4 segments, it's likely a direct drive type, i.e. shared common, every segment mapped to a pin.

    My opinion is that it's not worth the effort, except as a learning exercise. You might find that it complicates your project somewhat.
     
  4. dave

    Dave New Member

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  5. Mr RB

    Mr RB Well-Known Member

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    Have a look around some junk stores etc, just about every old fax has a 1x16 char LCD text display or a 2x16. These are a standard 14-pin pinout, use 5v supply and are easy to drive, even in assembler.

    Ohterwise you can get a 1x16 or 2x16 from Ebay for about $10 ??
     
  6. 3v0

    3v0 Coop Build Coordinator Forum Supporter

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  7. Triode

    Triode Member

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    Thanks for all the replies. I'm interested in this:
    Thats definetly something I would like to learn to do anyway. I'm going to look up what I can on this, but if you want to link me to any usefull info on it that would be apriciated.
     
  8. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    Check my tutorials, they show how to do simple serial to a PC (or anything else) - I often use such a scheme for debugging. An even simpler technique is to use a resistor and LED connected to a pin, and switch it ON and OFF at certain points through the program - obviously this can't display as much information though.
     
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  9. Triode

    Triode Member

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    I've been doing that actually, but like you said it is limited. Now that I'm going to be trying to figure out if its reciving ranges correctly and setting up A/D inputs a bit of a clearer view of whats going on could really help. I'll definitely check out your tutorial and see if I can get it running that way when I get home. I actualy have some various size male serial ports with pinch pins and some awg 22 that I could wire them to a bread board with, so if the software side of it isnt too tough hopefully I'll have it working soon.
     
  10. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    The software side is dead easy, and by using a software UART you can use any output pin.
     
  11. Sceadwian

    Sceadwian Banned

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    They can typically be used for crude graphics if it has character generator ram as well. In an emergency if the char ram isn't used the micro controller can use it.
     
  12. Mr RB

    Mr RB Well-Known Member

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    Looks good even with the 0.05" pitch, but the link that was selling the LCD's is gone;

    Picture of the display:
    http://www.allelectronics.com/mas_as...66.LCD-111.jpg

    Maybe they run out.
     
  13. Triode

    Triode Member

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    It could be a bit tough to debug my work when the pic software, the hardware and the PC program are all in question. does anyone know of a premade applet out there that will work with the serial port and display what it recives? Anything you have that can send data packets would be usefull too.
     
  14. blueroomelectronics

    blueroomelectronics Well-Known Member

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    What programmer are you using?
    The PICkit2 supports Debug on the 16F916 and has a built in UART tool. Pretty handy.
     
    Last edited: May 14, 2009
  15. Triode

    Triode Member

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    Right now I still have that cheap JDM programmer. I've been meaning to upgrade to a pickit2, but I so far don't know what the difference is between all the pickit2 versions, so I haven't ordered one yet.

    The junebug is your current main PIC programmer right? I might go ahead and get one of those. Being able to talk to the guy who designed it and get support here seems like a bigger advantage than I can see with any of the other models.
     
    Last edited: May 14, 2009
  16. blueroomelectronics

    blueroomelectronics Well-Known Member

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    Yes the Junebug is my best seller by far. It's a PICkit2 minus the variable 100mA VPP supply and I/O clamps (so it's 5V only) and internal EEPROM this was done to keep costs & kit complexity down. All parts are through hole so it's easy to build and repair.
    The Tutor was added as when I sold the Inchworm the first thing most people that bought one didn't know what to do next. So I included a small but very capable 18F1320 with a handful of switches / LEDs / pots carefully selected to demonstrate PIC I/O as best I could.
    The tutor can be disabled so the Junebug works as a standalone programmer / debugger.
     
    Last edited: May 14, 2009
  17. Sceadwian

    Sceadwian Banned

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    You should think about doing an SMD version blueroom. The cost savings for using SMD components will probably offset assembly costs. While through hole isn't dead, it's costly compared to SMD.
     
  18. Triode

    Triode Member

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    The only reason I dont use SMD components much is that theyre tough to prototype with. But I suppose if it were a kit that came with a board surface mount stuff would be fine.
     
  19. Sceadwian

    Sceadwian Banned

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    The space savings on the PCB's, and the lower cost would make up for any down sides, even if you had to pay someone to assemble them.
     
  20. blueroomelectronics

    blueroomelectronics Well-Known Member

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    Actually the next few kits will have some SOIC LM75 temperature and one TSOP 18F Ethernet (blech not a fan of solder those)
     
    Last edited: May 14, 2009
  21. Triode

    Triode Member

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    when are they going to make something that works like a printer but you load in some surface mount parts and solder instead of ink, and a board instead of paper, and it makes your board? Maybe I'll try it when I get a whole lot more advanced at making CNC machines.
     

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