Propeller Connection Question
NWCCTV
Posts: 3,629
I am trying to breadboard a Propeller Chip (http://www.parallax.com/product/p8x32a-d40)
for testing purposes and I am running in to issues. Can I temporarily leave the EEPROM disconnected and only connect the prop chip just for troubleshooting? Will it show up in Tools/Identify Hardware if my connections are correct?
for testing purposes and I am running in to issues. Can I temporarily leave the EEPROM disconnected and only connect the prop chip just for troubleshooting? Will it show up in Tools/Identify Hardware if my connections are correct?
Comments
It will run without the EEPROM. Just make sure you have all power and ground connections for ALL VDD and VSS, and that the Crystal is as close as possible to the chip.
And decoupling caps at power connections.
You should post the code you're using. How is the LED connected?
Have you tested the LED with a 3.3V source on its own?
Edit: I meant EEPROM in the first line not LED.
Power to both sides of the Prop?
Decoupling capacitors across the power at the chip?
Crystal nearby?
Are you getting good voltages (where you expect them) off your breadboard power supply?
Is it a known good Prop? (OK, sometimes this is hard to guarantee
Are you setting a clock in your test program or just using RCFAST?
Does your test program blink an LED on another Prop board? (It's on my checklist...I've been known to make coding errors)
It should work unless you somehow fried it from the start.
I run them without crystals and EEPROMs often so it is certainly a workable plan.
http://www.parallax.com/product/130-32305
I think this is what you are thinking of and years ago Parallax sold it as a kit.
http://www.parallax.com/product/32210
Do you mean something like this?
Wulfden Propeller Platform Through Hole Kit
Brian still makes them. He's a good guy and has good stuff. (Plus he speaks Forth!)
The PCB also works for a DIP40 Propeller chip as well if you use stacking headers and omit the QFN Propeller. I always meant to sell that as a bare bones kit, but since my profit is already essentially zero, I haven't done anything with that idea.
The only example I see on page 34 is the part with the push button. The push button on the far right breadboard could easily span the center divide and components connected to row 28 could be moved to row 29. I couldn't find any obvious problems with using five hole breadboads with the PEK.
edit: I see where the pushbutton in the bottom right would have to be rearranged though. It wasn't real obvious at first which holes it was pushed into. That type of button is a pain to use on any plastic breadboard. The leads are wide and flat, they just never fit tight.
All 32 I/O pins were available and the Propeller took up minimal board space.
Since the QuickStart has come out, I very rarely (if ever) use the above board (or ones like it) since I just set the QuickStart next to the breadboard and plug the wires into the QuickStart header. This way no breadboard realestate is used by the Propeller.
As long as the circuit doesn't require much current, I use the QuickStart's Vin pin for a 5V source and the Vdd line for a 3.3V source.
I have a bunch of QuickStarts I keep around for this sort of thing.
The Photo above used a small PCB SparkFun used to sell. Before making the board pictured above, I made one with a DIP chip.
It looks hideous but it works. The white header at the bottom of the board is for a Prop Plug and the black monstrosities near the top are heat sinks attached to the 5V and 3.3V regulators.
With the QuickStart, I often don't even use a breadboard. I just plug stuff directly into the QuickStart header.
IMO, the QuickStart has really made prototyping with the Propeller very simple.