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10 years, 1 month ago.
how i connect mbed nxp lpc1768 to GPRS Shield sim900?
i can´t comunicate between mbed and sim 900: i defined pin 9 and 10 as serial conect the tx (pin 9) to rx uart sim 900 and rx to tx ground the uart sim900 to ground mbed, set the jumper of uart sim900 the lights of the shield are on, set the program to get echo from pin9 and 10 but can´t get nothing. i'm using teraterm 9600 baud!!! what i'm doing wrong?
1 Answer
9 years, 10 months ago.
First of all, I am not sure if the mbed can handle 5v input, it would be wise to add a resistor divider like 1k and 2k2.
Second, the baud rate is probably the problem. Most libraries and examples scan the uart at different baud rate. Most easy way to do it is to scan from 2400 to 115200 baud and send the command "AT" until you receive "OK". If so, that's the baud rate you should use. There is a command to set the baud rate into the desired value e.g. 9600 so you don't have to scan next time the mbed powered on.
can i have your coding on connecting lpc1768 with sim900?
posted by Khalid Isa 19 Dec 2016