I have use this circuit.
If i connect to hyper terminal all works fine, but if i connect to pic don't work.
I have use this circuit.
If i connect to hyper terminal all works fine, but if i connect to pic don't work.
Why if i connect the DB9 connector to pc (hyper terminal) with rs232 cable all work?Originally Posted by savnik
If you have modified the Max232 to DB9 as per my previous post then you pic board now is a DTE device, and to connect to the PC, which is a DTE device you need to cross pin 2 with pin 3 in the connecting cable. Once you have a crossed cable you can check your board and program functionality using hyperterminal to send the "OK" once you receive the "AT" from the board. If this works and the TC35 works with hyperterminal it should work also with your pic board.
Remember that your TC35 is a DCE device and a DCE device is connected to DTE device with a cable pin to pin. Since you are very likely working without handshaking then you need only three connections on the DB9 (pin 2; pin 3 and pin 5)
Al.
Edited:
I looked once again to the picture you have posted and I noted on the left side a note "TO THE TC35". This is wrong. Pin 11 and pin 12 of Max232 must be connected to the pic, while Max pin 14 goes to DB9 pin 3 and max pin 13 goes to DB9 pin 2. This DB9 connector is the one you will use to connect your TC35
Last edited by aratti; - 4th December 2010 at 18:51.
All progress began with an idea
The attached picture will explain better how the connection have to done.
Cheers
Al.
All progress began with an idea
I reverse the pin 2 with pin 3 and now work.
Thank you.
I attach all the circuit wich is assembly in one pc board
Check that pic pin 18 is connected to Max pin 12 and pic pin 19 is connected to max pin 11.
Since it seems you have a wired PCB then very likely you are unable to change the DB9 connection, so cross the serial cable
Al.
All progress began with an idea
The pin 18 is connected to Max pin 11 and pic pin 19 is connected to max pin 12.
When connect the DB9 connection with hyperterminal and with those :
at
OK
at+creg?
+CREG: 0,1
OK
at+cmgf=1
OK
at+cmgs=xxxxxxxxxx
> hello my friend
+CMGS: 4
work very well.
When i connect to DB9 connection the pic don't work. I connect the pin 2,3,5 with pic pin 25,26 and ground (normal and cross)
I have code for AVR and for C8051 , but i don't know c language.
Last edited by savnik; - 4th December 2010 at 20:18.
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