Table of Contents:

• 1. Introduction
• 2. Why can't the password access AT command after upgrade(-NB)?
• 3. Version Confirmation
• 4. How to solve
  • 4.1 Method 1: Erase the chip before upgrading the firmware
  • 4.2 Method 2: Update the firmware directly and query the password via STM32CubeProgrammer

1. Introduction

This chapter describes why the password is wrong after upgrading the firmware and what to do about it.

2. Why can't the password access AT command after upgrade(-NB)?

Because the new version of -NB firmware has updated the factory reset function, users can choose to restore all parameters to factory Settings, or keep the password to restore the rest of the parameters to factory Settings.

This update changes the password address of the firmware, so the password will be invalid after the customer upgrades from the old version of firmware (without FDR1 function) to the new version of firmware (with FDR1 function).

Two different restore factory Settings configurations.

AT command:

• AT+FDR       // Reset Parameters to Factory Default.
• AT+FDR1     // Reset parameters to factory default values except for passwords.(new)

3. Version Confirmation

We are now dividing the old firmware(without FDR1 function) with the new firmware(with FDR1 function) by whether it contains FDR1 functionality. Please refer to the table:

4. How to solve

4.1 Method 1: Erase the chip before upgrading the firmware

The user can choose to erase all contents before upgrading the firmware and then burn the new version of the firmware. The user can still use the original password, but this method will restore all configurations to the default firmware Settings.

The chip can only be erased by updating the firmware through the UART TTL interface. See UART Connection.

Method of erasing full chip flash memory

• Connect to the STM32CubeProgrammer

• Select Erase full chip flash memory

After the erase is complete, download the new firmware directly.

• update firmware through UART TTL interface : Instruction.

4.2 Method 2: Update the firmware directly and query the password via STM32CubeProgrammer

If you do not want to erase the chip flash memory, you can also use the password address to query the password through STM32CubeProgrammer.

• The password address for old firmware(without FDR1 function) : 0x08019000
• The password address for new firmware(with FDR1 function) : 0x08025D00

Notice: The password can only be queried after the firmware is run once.

Procedure for querying the password(old firmware):

• After the firmware upgrade is complete, switch back to the FLASH and reset the node to run the new firmware once.
• Then place the switch at the ISP and connect to the STM32CubeProgrammer (same as when burning the firmware).
• Click "Device memory", enter 0x08019000 in "Address", and click "Read"
• Find the 0x08019000 address field and then read the current password as shown in the screenshot below.

Procedure for querying the password(new firmware):

Refer to the old and new firmware division above, and run the firmware first after updating the firmware.