Serout problem

[lerameur]

ok I did some changes this morning,
I changed the sending clock to 20 Mhz. I saw too that the transmission was too slow, how can I control anything with byte thats like a second. Now the bit rate is ok, I like it now, but then at the receiver I get a weired signal , a steady triangular form with lots of rise and fall time.
I added a picture of this and my circuit where i am probing
http://www3.sympatico.ca/lerameur/
My sending ciruit is just a few inches away.
ken

[skimask]

Are pins 6 and 7 grounded on the rx?

Where's your antenna?

And now I think you might be transmitting too fast. Check your OSC settings both in your source code and your fuse settings for the PIC.

The period of the channel 2 signal is 208.4us, which equates to 4798.4bps.

Multiply by 2 since you're using manchester encoding (or trying to), you get 9596 bps, very close to 9600 baud (within .03%).

Trying slowing down to 2400 baud and see what happens. Or if you're already there, try 1200 baud, then 9600, whatever. Try different characters. For instance, a $65 (%0110 0101) would be the manchester encoding pattern for a $4. The alternating bit patterns is the key to making the whole thing work and transmit data for you.

[lerameur]

I will home only tonight.
BUt I did gground pin 6 and 7, there is small wire going from one to the other then ground wire from that to the ground. I removed the antennas because I did not see any difference with or without since I am transmiting very close.
I did reduce the speed down to 2400 but same output.
I am tramsitting 10101010 , why is the 4th 1 is doubled.

On another note, I tried this sending code:
http://www.rentron.com/ruf-bot.htm
with same chip in picbasic and I still did not get a good receiving, Although when I tried it, I had a 4Mhz crystal, maybe adding a 20Mhz, BUt his code do not specidy any, so I assumed default. Could my receiver be busted?

ken

[Bruce]

The MAX reliable data-rate of the receiver you have is 2400 bps. Everything
you try should be at or below 2400 bps. Over the MAX data-rate is just not
going to produce anything reliable.

Have you tried testing your RF modules with the encoder/decoder ICs you
received with your kit yet? That's what we test them with here before kits
ship.

Before moving any farther, I would definitely recommend you validate your RF
modules by testing them with the encoder/decoder ICs you received.

Once you have verified that everything's working, it's a lot easier to move on
from that point.

[skimask]

The MAX reliable data-rate of the receiver you have is 2400 bps. Everything
you try should be at or below 2400 bps. Over the MAX data-rate is just not
going to produce anything reliable.

I beg to differ! Those modules rock! Even though they're only rated for 2400 bps, I've been using them at 9600 bps with very good reliability (if I had to guess, over 95%), althought 19.2kbps is more like around 50% but it still works!


Have you tried testing your RF modules with the encoder/decoder ICs you
received with your kit yet? That's what we test them with here before kits
ship.
Before moving any farther, I would definitely recommend you validate your RF
modules by testing them with the encoder/decoder ICs you received.
Once you have verified that everything's working, it's a lot easier to move on
from that point.

True, the encoder/decoder modules are handy. I was trying to get him up to that point, but it sounded like he might've had a dead module in the first place. And since he had the 'scope out and was watching it, I figured I might've been able to induce a failure that would duplicate what he might/might not have been doing right or wrong....

Keep at it....we'll get 'er eventually...
JDG

[lerameur]

hi,

I only had time to try one thing. I put a simple command with a decimal number and I included the encoder.
check it out:
http://www3.sympatico.ca/lerameur/

It is good, but the transmitter is right beside the receiver, I would expect a better reception, When I wil be putting this 100feet away, I am afraid I wont get a signal.
Also, I would like to get it working without the encoder. I want to understand why the way I was trying do not work.

ken

[skimask]

hi,

I only had time to try one thing. I put a simple command with a decimal number and I included the encoder.
check it out:
http://www3.sympatico.ca/lerameur/

It is good, but the transmitter is right beside the receiver, I would expect a better reception, When I wil be putting this 100feet away, I am afraid I wont get a signal.
Also, I would like to get it working without the encoder. I want to understand why the way I was trying do not work.

ken

I think it should've worked. I get the same type of output with the bit of roughness on the trailing edge of the pulses like you had before. BUT, the firmware in my receiving PIC gets the bytes just fine (remember the serial module in the PIC does a bit of oversampling of the bits, so if the leading or trailing edge is a bit messy, it won't matter much).
You might be too worried about the fact that the TX and RX signals aren't exact 100% matches of each other and not worried enough if the code in the receiving PIC works in the first place.
Have you tried making the Tx-PIC talk to the Rx-PIC without the wireless modules (or the encoder/decoder) in the middle? Does that work? If not, you probably have something wrong with your code.
Also, have you actually tried putting some distance between the modules to see if the receiving signal changes much? It might not...
JDG