Piggyback - dangerous or benign
Humanoido
Posts: 5,770
Consider placing one prop chip on top of another
where all the pins connect.
(take a look at the Propalyzer to see a piggyback
arrangement)
http://forums.parallax.com/showthread.php?p=788315
However, there are no protection resistors on the
I/O pins. There may be a condition when the output
pin is high and the input pin is low and smoke will
result. Is there a way to compensate this for safety
reasons?
Thank you for your replies.
humanoido
Post Edited (humanoido) : 2/21/2010 5:46:31 PM GMT
where all the pins connect.
(take a look at the Propalyzer to see a piggyback
arrangement)
http://forums.parallax.com/showthread.php?p=788315
However, there are no protection resistors on the
I/O pins. There may be a condition when the output
pin is high and the input pin is low and smoke will
result. Is there a way to compensate this for safety
reasons?
Thank you for your replies.
humanoido
Post Edited (humanoido) : 2/21/2010 5:46:31 PM GMT
Comments
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JMH
Good Luck.
humanoido
Assuming you mean to solder them in to stacks then you could probably bend the legs out flat, cut them a little short and solder small through hole resistors on each IO pin. Then make a PCB (or use veroboard) to go on each side of the block of propellers you have created, this would form the common between pins. The current being limited between any two pins by two resistors. That said if you make one pin high and all other pins low you may still have issues.
Graham
humanoido
Post Edited (humanoido) : 2/21/2010 9:06:52 PM GMT
SEMICONDUCTOR SOLDER/GLUE.
and
CARBON SOLDER/GLUE.
Once you figure out where to get these things, let me know.
I'd like a "dope your own silicon" kit myself.
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TERMS OF USE: MIT License
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The dsp/fpga king is dead, long live the prop.
humanoido
Post Edited (humanoido) : 2/22/2010 4:36:31 PM GMT
how about this for a space saver? 7.48x0.9" only 0.25" thick fully populated. All 8 props are off a single clock source and eeprom booted in series or they can be broken apart into 8 seperate props with crystal and individual eeproms.
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24 bit LCD Breakout Board now in. $24.99 has backlight driver and touch sensitive decoder.
If you have not already. Add yourself to the prophead map
Russ
fly wires would be needed for vdd,vss, and crystal but it would look cool.
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24 bit LCD Breakout Board now in. $24.99 has backlight driver and touch sensitive decoder.
If you have not already. Add yourself to the prophead map
Wow!!!
Wow!!!
I am absolutely blown away by these two great suggestions!
One thing is apparent, this forum has some of the greatest
minds in the world.
Cheap
Leave all IO Free
Multiple configurable
Lots of Props
I suceeded I think. Fully assembled boards would cost about $150 maybe less still working on pricing. But the PCB would only be about $15-$20 and all the parts I have used are fairly easy to hand solder.
All IO are free. SCL, SDA are on a common bus with P31 used to triger next devices reset. When broken apart theses 3 pins are completely seperate though and there are solder points.
The board has a brown out detection, reset button, and amplified crystal circuit on the left and 8 individual props to the right. props can be seperated into 8 seperate boards with crystals and eeproms each or kept as 1 board and utilize the common clock/eeprom. BOE circuit on each prop can be enabled or disabled on each board. though must be disabled if using as 1 single board(which is why I provided an external BOE circuit).
8 props.
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24 bit LCD Breakout Board now in. $24.99 has backlight driver and touch sensitive decoder.
If you have not already. Add yourself to the prophead map
1) the first section of the board has reset, crystal,
eeprom, and what is the remaining rectangular component?
2) What do you mean eeprom booted in series? Just one
eeprom or one eeprom for each prop?
3) In your opinion, regarding 8 props on the same crystal,
what is the performance reliability?
Thanks.
humanoido
*clock generator(crystal, inverter, shmit triger, and filter)
*Reset switch
*Brown Out Detector(Resets prop if voltage drops below 2.9V)
2) There are pads for 1 eeprom on each of the 8 prop boards but when used as 1 board only 1 is soldered on. The props boot up off the single eeprom in series 1 after the other. When boards are separated there can be a separate eeprom for each. This keeps cost down since you only need 1 eeprom for all 8 props.
3) I am not just using a crystal to drive 8 props. but instead have implemented a crystal based clock generator. The clock generator isolates the crystal from the props keeping it acurate as well as can provide more current and cleaner wave form to the props. There would be no trouble running 8 props off 1 crystal.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
24 bit LCD Breakout Board now in. $24.99 has backlight driver and touch sensitive decoder.
If you have not already. Add yourself to the prophead map
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
24 bit LCD Breakout Board now in. $24.99 has backlight driver and touch sensitive decoder.
If you have not already. Add yourself to the prophead map
I believe you have ushered in a new era
of multiple Propeller Chip - 44-Pin QFP
variety - board technology.
Congratulations!!!
humanoido
Propeller Chip - 44-Pin QFP
I would like to take a look at the schematic and components.
humanoido
humanoido
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Style and grace : Nil point
That search facility really needs to be fixed.
Doug