Can't decide if I love or hate this chip!
Conehead
Posts: 12
NOTE:·The title is misleading...the propeller is absolutely amazing.
The problem is that after months of circuit design, board layout, software testing and prototyping a data acquisition/stepper driver board using an ADuC845 (another really neat chip I love) I made the mistake of showing my boss how I could replace a clunky 3 board solution with a 1 board solution using the Propeller.
So here I am on a Saturday laying out a new board that will control 3 motors, read 12 differential 24 bit channels using 3 different ADS1256's and monitor 12 digital inputs.
Has anyone else experienced something similar, where after weeks or months of work, you simply start over because the Propeller was what you should have used all along?
The problem is that after months of circuit design, board layout, software testing and prototyping a data acquisition/stepper driver board using an ADuC845 (another really neat chip I love) I made the mistake of showing my boss how I could replace a clunky 3 board solution with a 1 board solution using the Propeller.
So here I am on a Saturday laying out a new board that will control 3 motors, read 12 differential 24 bit channels using 3 different ADS1256's and monitor 12 digital inputs.
Has anyone else experienced something similar, where after weeks or months of work, you simply start over because the Propeller was what you should have used all along?
Comments
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Propeller Wiki Rocks! - propeller.wikispaces.com
Welcome aboard! ... That's exactly the type of thing we like to hear!· Glad you are enjoying the Propeller.· Now when it comes time to performance reviews at your work, you can show how you cut the board real-estate down to 1/3 of the original design.
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Beau Schwabe
IC Layout Engineer
Parallax, Inc.
I'll post the analog front end schematic and the ADS1256 object when I finish.
This is what I did.
The board of the picture has:
19 digitally optoisolated, NPN or PNP configurable Inputs.
14 optoisolated and with zero cross detector plus triacs, outputs.
1 relay output.
3 outputs, pulse and direction each, to controll until 3 steppers motors drivers for axis positioning.
USB input form a PC (wich runs apropiate software for the machine).
1 Reset input.
2 5Vcc, for power inputs.
My old design had: 1 BS2SX, 3 Atmel AT8051, and 3 COP8 microcontrollres, now, all is in one propeller, I've many machines working with this new board without any problems. So for me, was a good choice to change for this impressive Pchip !!!.
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Regards.
Alberto.
All of this has now been replaced by one Propeller.
I have a bunch of other, personal, projects that are going to be redesigned soon. I'll post them as they get finished.
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Timothy D. Swieter, E.I.
www.brilldea.com·- Prop Blade, LED Painter, RGB LEDs, uOLED-IOC, eProto fo SunSPOT, BitScope
www.sxmicro.com - a blog·exploring the SX micro
www.tdswieter.com
I think I see the error of your ways...each of your ADuC845s could be replaced by a Propeller...
You have to think volume...gobs and gobs of Propellers...whatever the problem is... throw a Propeller at it[noparse]:)[/noparse]
Chip isn't going to release the PropII until he has sold all of the PropI-s and we all have to do our part.
And while you are at it... you could get rid of all that opto-isolation stuff with some high quality reed switches from Radio Shack.
Loved your post
Rich
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·"I have always wished that my computer would be as easy to use as my telephone.· My wish has come true.· I no longer know how to use my telephone."
- Bjarne Stroustrup
Talk to partsman... I don't know if his price point is exceptional enough, but he has a real cheap supplier for his little boards.
Rich
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·"I have always wished that my computer would be as easy to use as my telephone.· My wish has come true.· I no longer know how to use my telephone."
- Bjarne Stroustrup
Ditch those blue terminals, they suck. The green ones in the bottom right are much better, they utilise a rising-clamp mechanism, I prefer the plugged version myself. Speaking of which, You've socketed most of the ICs but none of the relays ...
Yes, but I only need to waste those blue terminals, I never used the plugged version...are they practique at the time of connect many of them ? or maybe are easy to use them with screws ?
I found those relays great, I never had to change any in many many time, I used them too in my old boards. About the IC's, that was the first board, it is working and I'm testing it, maybe in future I'll take out the IC sockets, maybe I'll use a QFP propeller & eeprom. Maybe in the redraw I'll change for two boards, one for CPU, and another for I/O's. All of this boards that I'm testing are working fine, so propeller seems to be very reliable in the industrial field.
In the next design I'm planning to avoid the PC, doing a most complete CPU, with SD card, VGA out, and a keyboard, also get the final size of the boards down.
Anyway this Pchip is great !!
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Regards.
Alberto.
The sort of plugged terminal I'm referring to is something like this. They come in pretty much any length from two terminals up to twelve or so.
Evan
Beware: Some are imperial in multiples of 5.04 mm and some are metric in multiples of 5.00 mm. Can be a bit frustrating getting them mixed up. Although, at low pin counts they are interchangeable.
I've been using the various ADuCs for projects requiring high quality A/D inputs for a few years. They're good chips and if I needed to only measure sensors, I would use one because of the integrated A/D.
However, I have to measure ALOT of sensors this time (up to 12 differential or 24 single ended) and at a high rate all while running 3 steppers and monitoring 3 up/down and 6 limit switches. The beauty of the propeller is that I have 1 cog each for the motors and their respective switches, 1 cog for communication to/from the PC, 1 cog each for the A/Ds and 1 cog left over (I'll find a use for it).
Not only does the prop make it a simpler design (I finished the schematic in 1/10 the time of the other one) but the darn thing runs so fast that I can run each motor at twice the speed I was able to with the previous design. The first thing I did was connect 1 motor to the prop demo board and write 20 lines of code to make it go forwards and backwards at twice the speed and communicate with the PC. I then explained to the other engineers and my boss (father) the concept behind the prop and the fact that I had 6 other "processors" left to run other motors or communicate with the A/Ds.
Dedicated counter inputs and PWM outputs? Who needs them. Count the pulses as you send them out.
Interrupts? Don't like and don't need them.
Still have to use FETs to interface with the motor, which uses 5V for the opto's inside it, but I had to use them with the other processor because it could only sink 1.3mA per pin.
The only problem is that I ran out of I/O lines for the motor enables because I wanted to have each A/D running all the time so I implemented 3 SPI buses. I am using the RTS pin on the FTDI chip to enable/disable all three, but I might change this.
I'll post the schematic when I've cleaned it up.
It's hard to remember that the Propeller might not be the "practical" solution for a project where the production costs are critical and the development costs are not, where the cost of development is amortized over thousands and thousands of finished products. There's very
little that the Propeller can do easily that can't be done with a much cheaper processor with a huge sweat equity along with possibly less
reliability that, from a support perspective, may never be seen.
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--Steve