Terminal not working (debug)
Jkane
Posts: 113
Hello,
I having trouble with a pcb board,
the circuit is the same as the one in the propeller education kit, page 27,
I checked all the grounds, power and pins, all connections seem good,
the propeller plug, connects fine, the board is found and you can download and run verify code to eeprom and ram, all works fine,
I am running the Parallel Terminal Serial demo, but I get no output back to the debug window,
I can run the update status and view info, all looks good, but no output, It is as if the propeller chip is not running and I don't really know what to check.
I also have the propeller education board completed, it works fine, and i check all the power, ohms and grounds and all seems the same.
so I missed something and i don't know what I can check to validate what is going on.
thanks
Jeff
I having trouble with a pcb board,
the circuit is the same as the one in the propeller education kit, page 27,
I checked all the grounds, power and pins, all connections seem good,
the propeller plug, connects fine, the board is found and you can download and run verify code to eeprom and ram, all works fine,
I am running the Parallel Terminal Serial demo, but I get no output back to the debug window,
I can run the update status and view info, all looks good, but no output, It is as if the propeller chip is not running and I don't really know what to check.
I also have the propeller education board completed, it works fine, and i check all the power, ohms and grounds and all seems the same.
so I missed something and i don't know what I can check to validate what is going on.
thanks
Jeff
Comments
Edit: Also check the crystal. You can blink a led at, say, 1 HZ, to make sure the crystal is right frequency.
I set up this for pin 6, first thing the code does, and the light does not blink, sadness
dira[6] := 1
repeat
outa[6] := 1
waitcnt(clkfreq*2 + cnt)
outa[6] := 0
waitcnt(clkfreq*2 + cnt)
After that we need to see your schematics, and code, and perhaps pictures of your final layout to see what is happening.
Everything below the repeat *IS* indented, yes? I see it is, in the quotes. That certainly should blink a LED, 2 seconds on, two seconds off.
Do you have an oscilloscope? or a meter?
Yes, I have both and a logic analyzer.
Jeff
Hello,
I checked the crystal, not working, so I have to replace it, but just in case it is not that, here is the code and schematics for the board
regards
Jeff
Yes, removing c5, it now works, as far as C6, I guess a C 104 is two small, any suggestions
thanks for you help,
regards
Jeff
Read this thread:
http://forums.parallax.com/showthread.php/131791-Another-one-of-those-decoupling-capacitor-questions.
especially Post #2 from Mike Green.
Edit: The Connection Diagram on page 8 of the Prop DataSheet does not show any bypass caps. I would have thought that something so important would have been covered there. Bypassing *is* covered in the Prop Education Kit Labs book, but in what seems to me to be an afterthought (after the I/O pins are tested).
Bypassing *has* been covered in the forum (Publison points to one of Mike Green's excellent discussions), AND good practice does dictate good power bypassing. Nevertheless, I think the official Parallax documentation is remiss in not covering it. In My Opinion.
ok, this board is a HCI (or will be) board, so it will probably run 4-5 cogs, I'll modify it and add note two suggested capacators. when I add all the code and have it running, I'll temp check it. I could lower the spec to 7 volts (using the propeller wall power supply), but let me finish up with what i got and I'll get back.
thanks for the help
regards
Jeff
You may be able to include a Cap on the back of the board very easily. (between Pins 9 and 12).
Either rotate the prop 180 degrees (because all the pins are coming out the other end)
Currently you have a 4 layer pcb. You should be able to do this in a 2 layer pcb. ( I am presuming this is a hobby board).
Preferably a 100nF bypass for the eeprom.
For your power LED use a 3K3 or larger - saves current and most superbright LEDs work fine with this. Consider adding another LED & resistor with the + end terminated in a pin - nice to be able to connect to any prop pin for simple debugging.
For excellent bypass for the prop, if you are using a socket for the prop, you can place a 100nF and a 1-10uF inside the socket opening directly across the power/ground pins for the prop. Both sets of power and both sets of ground (plus BOE) should go directly across between their pins.
When using a switch for reset, would be preferable to have a 10K pullup.
While it is not necessary the way the prop works, 10K pullups on both SDA and SCL lines (P29 & P28) are preferred.
Consider putting the transistor reset circuit on your board with a link to enable or bypass it. This permits you using a cheap USB-TTL module instead of the PropPlug. (BTW relabel it PropPlug). Consider adding 5V connector making a 5th pin for PropPlug (I place this above the GND connection and a NC the opposite end, making a 6 pin connector where the PropPlug uses the center 4 pins. This permits you using the 5V from USB provided by most USB-TTL modules. Provide a link to select 5V from USB or your 5V regulator, and conect the 3v3 regulator to the 5V output.
As has been said, no cap across the xtal is required.
BTW 12V in is typically too high. 7-9VDC is much better (or 5V from the USB)