Strange SerOut Problem

[masosi]

1) Are you sure you have pin 2 correct and pin 5 correct (you are using a 9 pin connector that is straight thru?) see http://www.airborn.com.au/rs232.html

Correct

2) Try it without TX connected

Will do again - didn't make a difference last time

3) A must - add a decoupling capacitor across VDD and VSS (10 uF should do or anything close to this)

Will do

4) You do have pin 5 connected to your PIC ground?

Yes

5) try another power supply that can be regulated (or 3 AA batteries in series)

Will do

6) Do you have access to an oscilloscope? see what is coming out of PortA.1 and pin 2 on the cable?

I don't have one unfortunately - an LED flashes like mad though...

7) Check your hyperterminal settings to make sure you have 300 selected and the parity off

Have checked that many times!

8) you have been using a crystal like in your sketch?

4MHz with capacitors as drawn

[masosi]

My computer won't talk to a serial modem anymore... and it won't echo its own data from Tx to Rx either...
That explains it!

Then a new question pops up... How was the serial JDM2 programmer verifying the PIC's contents? (I know the PIC was being programmed successfully too!)

Anyway, I'll get my hands on a new set of serial ports tomorrow

Skimask and Paul, thankyou so much for your help so far! I've learnt alot even though the ideas havn't solved my problem! Thanks again!

[mackrackit]

In post 5 I asked about the PC port, and you said that the same thing happened on another computer. ?????

As far as the programmer software reading back correctly, all I can say is it happens. I have a PICKIT1 that will read back errors if I use the software that microchip supplied, but mplab does not. Both software work. I would guess in this case the "lesser" software does not have something correct in its receiving side, like a checksum miss calc.

Again, check the signal with a meter. TX will show low (Maybe even a negative value) when idle and will spike anywhere from 2.5 to 25 V+ at transmit. If you have a machine less than 10 years old or using a usb/serial adpt, you will most likely see 2.5 to maybe 6.

[masosi]

In post 5 I asked about the PC port, and you said that the same thing happened on another computer. ?????

I know! I checked it and it was fine, and the other computer behaved the same... I must have stuffed that up! (Not sure how though!)

[masosi]

The new serial ports let everything behave as it should!
I wish I knew the port was dead 2 weeks ago!!!

Thanks again everyone, very good help

Regards,
Tom.