FX100 AT command ERROR

I am developing a tracking app on the FX100. I am connected to a microcontroller by 3 wire on the UART.
I use the AT+CREG? and the AT+CSQ commands to check status every minute or so.
I have not been able to determine the conditions it happens but occasionally the modem will respond to ALL of my AT commands with ERROR
AT itself gives OK - But every other AT command I try responds with ERROR until I power down
AT+CFUN is also produced ERROR so I cannot reset it.

Anyone experience anything like this ??


Hi sapike,

Could you please try sending “AT+WDWL?” and “ATI” when issue happens?

If it give proper response for +WDWL, the modem maybe entered download mode.
But to find out the reason, more information is needed, e.g. FW version, trace, etc…

If you have distributor or FAE associated, please contact them to analyze the issue.

Thanks for replying

Modem is now in THE state.

ATI gives
[0D][0A]OK[0D][0A][0D][0A]Sierra Wireless[0D][0A][0D][0A]FX100 Product[0D][0A][0D][0A]OK[0D][0A]
AT+CCLK? gives
AT+CREG? gives
[0D][0A]ERROR[0D][0A] ** Note no OK
AT+CCLK? gives
[0D][0A]ERROR[0D][0A] ** Note no OK
AT+WDWL? give

it appears to get out of step occasionally - sending no response sometimes and then two
eg ATI - wait 3 seconds ATI gives
][0D][0A]Sierra Wireless[0D][0A][0D][0A]FX100 Product[0D][0A][0D][0A]OK[0D][0A][0D][0A]Sierra Wireless[0D][0A][0D][0A]FX100 Product[0D][0A][0D][0A]OK[0D][0A]

I have to leave the office I will leave it on for a while and see what happens


Well, if it’s said “ERROR” it wouldn’t also say “OK” - would it?!

Is the microcontroller careful to always wait for the Terminal Response to one command before issuing its next commancd :question:

This problem is just not going away -
Basically the responses I get from the Modem do not appear to be in step with the query.
I have heard on the grapevine that there is a problem with a serial buffer not being cleared on the FX100

There is apparently a beta fW out there with a fix …

Come on guys - leave me hanging for months chasing a ghost and somone knows that
there is a serial buffer problem !!!

My only solution is to reset the modem, when it happens - great solution

If someone knows about the serial buffer - not clearing problem - please fess up please…

An siwi release it.

More to this problem.
When the modem gets into this phase…
I can send 3 character AT Commands such as ATI, ATA and ATH which will get a correct response -
4 or more character AT command (AT+WIND?) Get ERROR or no response despite correct syntax and leaving enough time

Please see the output log - where M>>> is the string sent to the Modem and
M<<< is the received string - comments after the<<<

5:37:52.208, M>>>ATI[0D]>>>
5:37:52.288, M<<<[0D][0A]ERROR[0D][0A]<<< // this appears to be the response from the previous AT command

5:37:54.500, M>>>ATI[0D]>>>
5:37:54.578, M<<<[0D][0A]Sierra Wireless[0D][0A][0D][0A]FX100 Product[0D][0A][0D][0A]OK[0D][0A]<<< // the response to the previous AT command

5:38:02.301, M>>>ATI9[0D]>>>
5:38:02.380, M<<<[0D][0A]Sierra Wireless[0D][0A][0D][0A]FX100 Product[0D][0A][0D][0A]OK[0D][0A]<<< // the response the previous ATI command - but not correct

5:38:04.251, M>>>ATI9[0D]>>> // at command > 4 characters - no response
5:38:09.352, M>>>ATI9[0D]>>>
5:38:10.293, M>>>ATI9[0D]>>>
5:38:11.146, M>>>ATI9[0D]>>>
5:38:14.673, M>>>ATI[0D]>>>
5:38:15.844, M>>>ATI[0D]>>>
5:38:15.904, M<<<[0D][0A]Sierra Wireless[0D][0A][0D][0A]FX100 Product[0D][0A][0D][0A]OK[0D][0A]<<<

5:38:19.416, M>>>AT+WIND?[0D]>>>
5:38:19.498, M<<<[0D][0A]Sierra Wireless[0D][0A][0D][0A]FX100 Product[0D][0A][0D][0A]OK[0D][0A]<<< // response to previous ATI command
5:38:22.068, M>>>AT+WIND?[0D]>>>
5:38:22.129, M<<<[0D][0A]ERROR[0D][0A]<<<
// sometimes AT command > 4 characters generate a response of ERROR other time nothing

Can anyone help - this is driving me crazy(er)

Is the microcontroller careful to always wait for the Terminal Response to one command before issuing its next commancd :question:

Hi Awneil,

it is possible that at times the microcontroller doesn’t get a response - and then issues another command.
But as you can see from the times on the log - the AT query commands are sometimes seconds apart.

I am trying the latest release beta firmware - There have been some modifications to the serial interface apparently