User's Guide

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LM074 SPP with GAP Central Application v1.1

5.3 Possible Failure points and corrective actions

The following section describes the possible failure points while

performing an Over the Air firmware upgrade. It also covers possible

reasons for errors what a user can do to correct them.

5.3.1 Failure point 1:

i. After entering the escape sequence “+++”, the module should

respond as OK and enter in Online-connected-command-mode.

ii. If module does not respond as “OK” (it will not reply as “ERR” in

this state), module is still in “online-connected-data-mode” and

sends data to remote device.

iii. PIO-xx is toggled or LED D10 starts blinking to show the module is

ready to accept the escape sequence.

iv. User should enter escape sequence immediately after the D10 led

starts blinking.

v. If module does not reply as “OK”, user should wait till module is

ready to receive next escape sequence.

vi. Module is ready to process firmware upgrade even if there are

multiple attempts of failure to enter in Online-connected-

command-mode.

vii. User cannot process further steps if module does not enter in

online-connected-command-mode.

Note: If the Current firmware on the LM074 module is a Bridge

application or GAP-Central-Only, then after SPP connection the LM074

enters into Command mode. Then there is no need to enter the Escape

sequence. The user can directly issue the “AT*upgrade” command.

5.3.2 Failure point 2:

i. Once the module enters into the Online-connected-command-

mode, the user should provide the firmware upgrade password

through AT commands.

ii. If the user provides the correct firmware upgrade password, the

module responds to the command as “OK” and displays the

message “Ready to receive OTA file”

iii. The module replies as “ERR”

a. If the user enters a wrong password for upgrade command,

module responds as ERR.

b. Firmware upgrade password is dependent on current

firmware version of the module.

c. E.g. if the current firmware version on the module is “1.50”,

the firmware upgrade password will be

“AT*upgrade=LMUPDATEV150”.

d. In the “AT*upgrade” command the string after “=” is case

sensitive and should be entered in all uppercase (for letters).