- Fri May 11, 2012 4:53 am
#144307
Hardware:-
The TxD (modem) line is pulled low and connected to the RxD pin in the processor
The RxD (modem) line is pulled high and connected to the Txd pin in the processor
RTS / CTS lines are left floating
Firmware:-
The USART is configured to operate Asynchronously at a baud rate of 115200, 8_bit, no parity, 1 stop bit.
Power on Sequency :- Enable regulator -> delay 200ms -> set ON_KEY -> delay 2000ms -> clear ON_KEY -> delay 2500ms return;
After power on, the Command_Ready LED (GPIO10) lit constantly, and the following message is received by the processor
“ SystemInit
+ADSYS: BK=0x1,0x11, RV=0x1, Fail=0x0
+ADSYS: FLASH VERIFY OK
Ready”
At this point I try to send the characters “at\n\r”, yet I don’t get a response from the modem.
When the same firmware is run while looping the TX and RX lines from just before the modem, I receive the transmitted characters. (External Loop works) But when the modem is inserted instead of the external loop, I don’t get any appropriate response.
Would you have a sample program code which I could use to get a clearer picture of what I need to do? Any help in this regard would be most valuable.
Many thanks
Best regards,
The TxD (modem) line is pulled low and connected to the RxD pin in the processor
The RxD (modem) line is pulled high and connected to the Txd pin in the processor
RTS / CTS lines are left floating
Firmware:-
The USART is configured to operate Asynchronously at a baud rate of 115200, 8_bit, no parity, 1 stop bit.
Power on Sequency :- Enable regulator -> delay 200ms -> set ON_KEY -> delay 2000ms -> clear ON_KEY -> delay 2500ms return;
After power on, the Command_Ready LED (GPIO10) lit constantly, and the following message is received by the processor
“ SystemInit
+ADSYS: BK=0x1,0x11, RV=0x1, Fail=0x0
+ADSYS: FLASH VERIFY OK
Ready”
At this point I try to send the characters “at\n\r”, yet I don’t get a response from the modem.
When the same firmware is run while looping the TX and RX lines from just before the modem, I receive the transmitted characters. (External Loop works) But when the modem is inserted instead of the external loop, I don’t get any appropriate response.
Would you have a sample program code which I could use to get a clearer picture of what I need to do? Any help in this regard would be most valuable.
Many thanks
Best regards,