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EHS6 startup | Thales IoT Developer Community

January 4, 2015 - 1:34am, 2224 views


I have a new design and I can't get the EHS6 to respond to AT commands. On startup I drive AUTO_ON low and see ^SYSLOAD and ^SYSSTARTING at 115200 baud. Then there is no response when I send a AT<CR> (tried both 9600 and 115200 baud). I had RTS0 connected but have removed any connection to RTS0 just to rule out flow control issue (RTS0 is low as  would be expected due to it having internal pull down). I'm monitong RX and TX with a scope so I know that the AT commands are getting to the modem on the TXD0 line. What is strange is the behaviour of CTS0 at startup, here is the sequence:

At startup CTS0 is low for 2 seconds then goes high,

^SYSLOAD and ^SYSSTARTING are output on RXD0 at 115200 baud

CTS0 reamins high but pulses low for 3 to 4 mS about every 2 seconds.

Why would CTS0 go high and what is the pulsing every 2 seconds? Is it waking from sleep every 2 seconds or something? Could the modem have been suplied with some JAVA application that is taking over ASC0? The EHS6 is fresh from the supplier.

Any suggestions appreciated. Regards Trevor.