Is It Possible???

James Henry

Ok i got my processor but the Prop Plug is on back order. i have tried to use the serial to prop stuff, but couldn't get any of the many variations to work.· which leads me to my next question.· Can i use My BS2 Homework Board to write a program to the prop or to the external eeprom???

Peter Jakacki

The 2 circuit published in the datasheet V0.3 works. You didn't say what happened when you tried to program the part? (what worked, what didn't). Also, have you wired up the prop correctly?

*Peter*

"Given two adequate solutions, the correct one is the simpler." Leo Brodie, Thinking Forth.

James Henry

The IDE dows not see my chip, i have checked and rechecked my circuit for 6 hours now, and it still doenst work, could it be because im using a radio shack USB to Serial. Works with my homework board

Martin Hebel

A standard USB to Serial device is NOT meant for use directly with the propeller. It's meant to replicate a DB9 COM port of up to +/- 12V, inverted data, though actual values may vary, it could be quite damaging to the Propeller's 3.3V architecture. The only approved device without making one yourself are Parallax's PropPlug/Clip or USB2SER with some pin changes.

-Martin

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
StampPlot - GUI and Plotting Software
Southern Illinois University Carbondale, Electronic Systems Technologies

Peter Jakacki

I'm guessing the USB Serial is plugged into the 2 transistor circuit and if so then that's ok. The problem may very well be your Radio Shack USB Serial cable, do you know what controller it uses? The prop bootloader uses timing pulses that some USB Serial converters might not handle well or fast enough. Both the FT232 and CP2102 based USB Serial converters definitely work.

*Peter*

"Today, make it work. Tomorrow, optimize it" Leo Brodie, Thinking Forth.

James Henry

The two transitor circuit doesnt seem to work, out of curiosity i measured the voltages on the reset bun and im getting about .34 V and 2.8 on the 3.3V pin on the chip.

the voltage on the usb adapter coming in on the dts line is -6.78V.

i even tried the 3 transitor circuit. and the same results! The USB To Serial Adapter Chipset i have no clue what it uses, windows device manager does not tell me any usefull information.

·Also i noticed if i leave the adapter plugged in it slowly pulls all power from the circuit, meaning if i monitor the 3.3V it drops over 35 seconds to 0V


Post Edited (James Henry) : 9/29/2007 10:49:00 PM GMT

Peter Jakacki

What you are saying doesn't make sense. How can the adaptor pull power from the circuit unless you have wired up things incorrectly? Are you supplying your propeller and circuit with a regulated 3.3V? (just checking).

That voltage dropping over 35 seconds is not possible unless perhaps your regulator is underrated and going into thermal shutdown, but what's drawing all that current?

Can you post your prop circuit and a picture of it so we can verify that it is correct?

*Peter*

"Shot from a cannon on a fast-moving train, hurtling between the blades of a
windmill, and expecting to grab a trapeze dangling from a hot-air balloon. . . I
told you Ace, there were too many variables!" Leo Brodie, Thinking Forth.

James Henry

Harrison.

Are you sure thats a 0.1uF capacitor on the DTR line? It looks like an electrolyte > 1uF or more. Using a cap with a large value may be causing the Propeller to not reset correctly.

James Henry

nope the cap is a 0.1uF

Peter Jakacki

Jim, I'm sure even an old camera like the DMC-F7 will do a better job than that in taking a picture. Use macro and flash and zoom in a bit so you can position the camera far enough away for the flash. Either way the circuit diagram is still missing.

Hey Harrison, you actually made out which cap was which from that picture?

*Peter*

Harrison.

I made an educated guess which was the cap by looking at the serial plug and the round shape of the cap. I didn't see any non-polarized caps in that picture so I made the assumption that it was an electrolyte cap that wasn't 0.1uF.

Check to make sure your BOEN and VSS pins are actually tied to ground. If they aren't then the built in pullup on the Reset pin won't be enabled, thus the reset signal could go all funky since the capacitor would just float there. Not to mention the Propeller would probably go into all sorts of weird reset patterns.

But other than that, a better picture is defiantly needed. I could barely make out some of the wires on the current picture.

Post Edited (Harrison.) : 9/30/2007 5:06:52 AM GMT

Harrison.

James, I can't see that image you posted. Seems your server isn't accepting port 80 requests from the outside.

James Henry

Sorry

deSilva

Just BTW:
(1) You connect reset to pin 4 of the rs-232 plug. This pin is sometimes erroniously labelled DTR, but it is not! It is RTS! Many cables shortcut them internally but some do not.
So change the setting of the Propeller tool to RTS or RTS&DTR just for a try!

(2) I already said I do not like this cap-only reset. I can work, but it should be much more reliable to add an "open collector" NPN behind it - not much work...


EDIT
Oops I have to change my first remark here Pin 4 of the 9p plug is of course DTR
There once was a time where I knew most pins by heart - of the 25p plug i.e. And pin 4 was RTS
Sorry :-(

Post Edited (deSilva) : 10/1/2007 8:14:42 PM GMT

James Henry

Still No Dice On All Setting, Added the NPN to the circuit and nothing.

Harrison.

Try replacing the electrolyte capacitor with a ceramic cap. There has got to be something funky going on with the reset circuit.

Also try shorting the tx/rx together and seeing if you loopback (open a serial terminal and see if it echos your characters back). If it doesn't then you have some sort of pinout/power problems.

Peter Jakacki

Where is that second reset wire running to? One runs down to that cap (bottom center) which looks suspiciously like a large value electro contrary to what you may say. The other runs up the top to I think the header in the top left hand corner.

Are the transistors emitter and collector swapped? The way you have them wired could be right but most of my transistors are opposite to that. If they are proper 3904/06s then it should be ok. (Hey, don't mix the npn and pnp thing)

I'm guessing that the db9 is a female, it would have to be.

From what I can trace of your circuit everything except the cap looks right. Just please please change the electro for one of those ceramics that you have lying under the board.

*Peter*

James Henry

Replaced the Capacitor and still not working, did the TX to RX loopback and it worked, does anyone know what the voltage should be at the RESn pin on the prop, i am using true 2n3906, and 2n3904.
Also i tried to write a demo application and save it as an binary compiled file, took the 32K of data and programed it onto the 24LC256, with the BS2 BOE, it wrote sucessfully but does not seem to load up on the propeller.

why does the prop plug have to be on back order

Should pins 7 and 8 from the adapter be tied together???

Post Edited (James Henry) : 9/30/2007 9:51:48 PM GMT

deSilva

James Henry said...
...save it as an binary compiled file, took the 32K of data and programed it onto the 24LC256, with the BS2 BOE, it wrote sucessfully but does not seem to load up on the propeller.

Hmm.. that seems to confirm something goes really wrong with the reset.
RESET is normally pulled-up by an internal resistor to 3V3.

Only in the cases when the PC takes over, I small pulse is generated to reset the Prop. As the Propeller Tool in the PC assumes that the Bootstrap has come up the the Prop, this pulse must not be too long.

Can you messure these sitations at the reset pin?

James Henry

Hmm.. that seems to confirm something goes really wrong with the reset.
RESET is normally pulled-up by an internal resistor to 3V3.

Only in the cases when the PC takes over, I small pulse is generated to reset the Prop. As the Propeller Tool in the PC assumes that the Bootstrap has come up the the Prop, this pulse must not be too long.

Can you messure these sitations at the reset pin?

I do not have an oscilascope, just using a voltmeter, which is very slow, when i test it i see a small drop in voltage on the reset pin.
using the negative lead across the casing, and the positive lead to the pins
Pin···· Voltage
1······· 0V
2······· 0V
3······· -6.30V
4······· -6.30V·······
5······· 0V
6······· 0V
7······· -6.30V
8······· 0V
9······· 0V

deSilva

All right, that is the situation at the D-connector which looks good and as expected.
But what at the Prop? Especially Pin 11 (Reset)

And just BTW: As you have 0V at Pin 2 of the D-Plug... You have not connected the recommended 4k7 resistor between Pin 2 and 4. Though it should not matter for this case I just mention it....

Post Edited (deSilva) : 9/30/2007 10:35:11 PM GMT

James Henry

At The Prop
Without With
Pin Adapter Adapter
3.3V 2.55V 2.49V
RESn 0.45V 0.09V
P31 3.27V 3.10V
P30 2.76V 2.6V

VR 3.3V 3.3V
(VR = Voltage Regulator)

deSilva

That looks terribly bad...
You can't have anything different at the Prop's 3V3 pin and the voltage regulator. There is just a wire inbetween!

deSilva

I just had a look at the photograph you posted...
How did you connect both parts of the 3V3 power stripe. You are aware that it is disconnected in the middle, aren't you?

James Henry

Nice Catch

Voltages Look A Lot Better but still no comunication
3.3V all across now


Post Edited (James Henry) : 9/30/2007 11:17:09 PM GMT

Peter Jakacki

Sorry, I don't use these breadboards so I don't really know but does that mean that the ground strip is disconnected too?

*Peter*

deSilva

No It is clearly marked at the stripes.
The idea behind it is to allow for two different voltages.... No need to have two different grounds

P.S.: But I think I have also seen boards whith both lanes disconnected... They have printed a "W" at that position... Most likely the Chinese glyph for: "Ha, ha , gotcha!"

Rayman

I had trouble too... Found that adding 0.1 uF between reset and ground fixed it:

http://forums.parallax.com/forums/default.aspx?f=25&m=218483&g=218781#m218781

James Henry

I Just want to take some time to thank everyone so much ecspecially deSilva
for that awsome catch on the missing power rails.

I Now Have It Working Using The 3 Transistor Circuit From Datasheet 0.1

thanyou Once Again.

now its time to play <GRIN>

deSilva

@Rayman: I already told you in the other thread that your solution is somewhat doubtful... I accept that it now "works" but you should investigate in this further when you can spare some time...

@James: You gave an indication of the problem yesterday at 3 o'clock; but we all ignored it....