315 mhz data transmission failed ... any comment

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transmitter side LPC 2106 message is may day may day EP-3 .... repeat

db-9

pin2 txd
pin 5 gnd

push the reset



receiver side is connected a DB-9 and realterm, 9600 XP windows based system
( any rate that I possible that I can think of) 8n1 .

use usb 5V power

pin 3 rxd

pin 5 gnd

result: nothing, no garbage in realterm what so ever and I do not know why?

the lpc 2106 microcontroller run very steadily, unplug everything

both modules are about 1 meter apart, try tera term too. no results. any
comment.



Re: 315 mhz data transmission failed ... any comment



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Are you sure you have the right assignment for pins 2 & 3?

Re: 315 mhz data transmission failed ... any comment


Straight Through (DB-9)

 DB-9                  DB-9
 Female                Male
--------              --------
 1   CD  ------------ CD     1
 2   TxD ------------ TxD    2
 3   RxD ------------ RxD    3
 4   DTR ------------ DTR    4
 5   Gnd ------------ Gnd    5
 6   DSR ------------ DSR    6
 7   RTS ------------ RTS    7
 8   CTS ------------ CTS    8
 9   RI  ------------ RI     9
Crossover (DB-9)

 DB-9                 DB-9
 Male                 Male
--------              --------
 1   CD  ------------ CD     1
 2   TxD ------------ RxD    3
 3   RxD ------------ TxD    2
 4   DTR ------------ DSR    6
 5   Gnd ------------ Gnd    5
 6   DSR ------------ DTR    4
 7   RTS ------------ CTS    8
 8   CTS ------------ RTS    7
 9   RI  ------------ RI     9



Re: 315 mhz data transmission failed ... any comment



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Interesting - every document I've ever seen shows pin 2 as RxD and pin 3 as TxD
on a 9-pin D.

Re: 315 mhz data transmission failed ... any comment


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your PC will be looking for RS232 logic levels on the serial port,  
is that what the receiver produces?


Bye.
   Jasen

Re: 315 mhz data transmission failed ... any comment


Hi,
a few things to look at: ( you using an lpc development board like an
lpc-mt-2106? - some of the points below assume you are)

1) use lpc sample code that uses 232 to enusre it's not your code at fault
2) make sure your terminal program isnt using any handshaking, ie xon-xoff
or hardware.
3)  if you have an oscilloscope use it to see if data really is coming out
of the lpc
4) if no o-scope, drop the baud rate as low as possible and use an led ( and
a resistor if needed) to see if you can observe data being tx'd ( if low
enough could probably use a mulitmeter to see the data too)
5) pin outs
       d9   d25
txd   3      2
rxd   2      3

if the lpc is a dte then connect
lpc     pc
txd to rxd

if its a dce then connect ( pretty sure the lpc is NOT dce)
lpc    pc
rxd to rxd


6) if the lpc was working and now isn't (which appear to be the issue - from
your post i believe it was hooked up to a transmitter at one point and
working) then try the following
7)check the voltage test points on the lpc, the 3.3 and 1.8v in particular.
8) if they're ok, then check the data going into the max232  (with the
oscilloscope) to see if it's toggling correctly, may be a dead max232?
9) if the volts are ok and the data into the 232 isn't toggling then the arm
is most likley cactus, try some sample code that runs the buzzer or other
bits n pieces on the lpc


good luck
Greg


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