View Full Version : Problem with a simple serial application

01-12-2009, 05:39 AM

Please bear with me, as I have no experience with controllers whatsoever - in fact, if I succeed with this program, I will not touch low-level stuff for a long time...

I am trying to write a simple program for Brilldea's excellent LED Painter. The creator of the LED Painter has provided me with the drivers which allow me to control the board - it all works very well.

However, I do not wish to go the DMX route - I would like to control the board directly with the Prop Plug. I thought that it would be relatively simple - just get the data and adjuct the LEDs accordingly... Unfortunately, it did not go that well... I cannot even establish a proper serial communication. For example, I try to test FullDuplexSerial procedures (with a Pure Data and with a simple VB app):

Serial.start(31, 30, 1, 9600)


test := Serial.rx

if test <> 0

Serial.tx (test)

The values I get back are certainly not what I send out - in fact, they are quite random, even if I send the same value all the time... What am I doing wrong?

01-12-2009, 05:49 AM
Hello Jabberwork,

the third parameter in serial.start is the mode

'' mode bit 0 = invert rx
'' mode bit 1 = invert tx
'' mode bit 2 = open-drain/source tx
'' mode bit 3 = ignore tx echo on rx

with value "1" you inverted the rx-pin

try it with ,ode 0

Serial.start(31, 30, 0, 9600)

and be sure that you have the same baudrate in your VB-App

another hint:

you have to set these constants
as without them the propeller runs in internal oscillator mode, which has NO accurate frequency

_clkmode = xtal1 + pll16x
_xinfreq = 5_000_000

best regards


01-12-2009, 07:31 AM
Thank you, the mode was wrong indeed. Now it works as it should!