View Full Version : Serial Output using FullDuplex and Schematic from website.

R Pankau
10-15-2006, 10:44 AM
I thought I'd try to send some serial data to hyperterminal via Pin 30 since it was already tied to my computer's serial port with a 2N3906 to translate the voltage for programming.· What I found was the chip would send serial data nicely as viewed with a scope, but when Hyperterminal was active on that port the receive pin 2 of the 232 line went high and stayed there.· I noticed that when I do an F7 in the Prop Tool (identify chip) the line will go that high briefly·but then it is released it looks like so the chip can modulate the line.· I'm guessing that the DTR Line may be hosing up the works???· I'm not reallly sure, or maybe Hyperterminal is just set up incorrectly.·· I never did really see what the port settings should be while using FullDuplex.· I guessed 8 data no parity 1 stop· no flow.·


R Pankau
10-15-2006, 11:05 AM
I just found the signal while Hyperterminal is connected but the diff between a mark and a space is only 0.5V.· While just communicating with Prop Tool the diff is 8.0Volts.·· I guess this is why data is not showing up at Hyperterm. but I'm wondering still why the low voltage???··

10-15-2006, 11:17 AM
· Yeah! THAT is your problem, Back in the old days of the Coco we HAD to pull up DTR via a 10k otherwise the Coco would NOT get the datahttp://forums.parallax.com/images/smilies/turn.gif

··· you need a Serial connector wired like this one:··short rts and dsr to··dtr· pin 6 and 7· to dtr pin 4 other end along with Rec, now since you are not sending a

··· DTR signal you have to pullup the DTR line with a 10k resistor to 5v + used to drive us nuts as one would get one end right and you would get data at one end

·· ·but not the other using a terminal setup on OS-9. voltage is not that much a problem since you are not following the standard!··running at 5v worked fine and even 2v

··· worked...since we were not using rs232 drivers!

·· Cheers Dennis


Post Edited (cocokiwi) : 10/15/2006 4:25:26 AM GMT

R Pankau
10-16-2006, 08:49 AM
Thanks Dennis,

I tied DTR to 3.3V and I do get data now.··