The NXP S32K14x series is a scalable family of 32-bit ARM Cortex-M4 based MCUs targeted for general purpose automotive and high-reliability industrial applications.
There are some special requirements that need to be fulfilled in order to use the device series with J-Link:
- Reset pin of MCU needs to be connected to reset pin of J-Link. If this is not the case, proper target connection cannot be guaranteed
ECC protected internal RAM
The device series provide ECC protected internal RAM. By default, J-Link resets the MCU on connect and initializes the RAM contents to 0x00. This is done for the following reasons:
- If a memory window in the debugger is open during the debug session and points to a non-initialized RAM region, on the next single step etc. a non-maskable ECC error interrupt would be thrown
- J-Link temporarily uses some portions of the RAM during flash programming and accesses to non-initialized RAM areas would throw non maskable ECC error interrupts
Readout protection of internal flash
The internal flash of the S32K14x series devices can be protected against unwanted readout accesses. The readout protection is configured via the option bytes placed at addr. 0x400 - 0x40F in the internal flash of the devices.
Enabling protection in production
Make sure that the application image that is programmed contains a value not equal to 0xFE to be programmed to addr. 0x40C. Make also sure that for the device selection in J-Flash etc. the variant S32K... (allow security) is selected. If this is not the case, J-Link will inhibit that the readout protection of the device is set.