Recovery mode for S32K328

[MorcinM]

I am new in S32K3x programming. My question are:

1. Why this so called Recovery Mode is needed in therms of device programming/flashing? Isn't MCU always accessible using debugger or this can be restricted for production firmware and recovery mode is the only way to flash new firmware/reprogram  in that case?

2. For the device/MCU already in recovery mode: can be in that case the s32k328 programmed using JTAG or it supports also flashing via UART (meaning: NXP build in support for UART programming)?

Thanks in advance for your support.

Regards,

Marcin

[VaneB]

Hi @MorcinM 

The recovery mode allows the host to recover from abnormal situations. There are two recovery modes: Secure Recovery Mode and JTAG-Based Recovery Mode.

Secure Recovery Mode:

• In this mode, the HSE subsystem boots the Secure Recovery Application after its authenticity is confirmed against ADKP.
• This mode must be enabled using the HSE_SECURE_RECOVERY_CONFIG_ATTR_ID attribute. The start address and size of the secure recovery application must be provided in the IVT (Image Vector Table).
• When this mode is activated, the application core is released at the start address of the Secure Recovery Application.
• If Secure Recovery Mode fails, the device will automatically enter JTAG-Based Recovery Mode.

JTAG-Based Recovery Mode:

• In this mode, the HSE subsystem waits for a debugger connection (which must be authenticated when the LC is in OEM_PROD or IN_FIELD).
• Once the debugger is connected, the HSE releases the device from reset at a predefined address, JTAG_RECOVERY_START_ADDRESS, to a RAM-based application with the application core in sleep mode.

For more detailed information on these modes, refer to section 2.6.1.3 (Recovery Mode) of the HSE_B Firmware Reference Manual, Rev. 2.4.

BR, VaneB