How can I flash the NXP S32K148 using J-Link? - cortex-m

Question

I'm working on a S32K148 with VS Code and J-Link. This is part of NXP's S32Kxxx series of 32-bit ARM Cortex M4-based MCUs targeted for high-reliability automobile and industrial applications.
I want to flash the chip using JFlash (with J-Link), but it seems that flashing has been disabled.
My research suggests that I need to have a LinkScript file for the S32Kxxx device, but I cannot find such a file anywhere.
Is my assumption correct that a LinkScript file is needed? If so, where can I find this file?

Answer 1

First, you need to ensure that the MCU's reset pin is connected to the reset pin of the J-Link. Without this done properly, you will not be able to connect via J-Link.
Next, it must be noted that the design of the S32Kxxx series makes it impossible to attach to a debugging session via J-Link out of the box. The Segger wiki contains a more detailed description:
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
Attach to debug session
For the reasons mentioned [above, in the section "ECC protected internal RAM"], no out of the box attach is possible. This is because there is no way to distinguish between an attach and a connect.
To attach to the device the following J-Link script file can be used:
File:NXP_Kinetis_S32_Attach.JLinkScript
Note:
This script file is only supposed to be used in case of an attach, as it skips the device specific connect.
So, your research is correct: in order to attach to the device, you must use a J-Link script, which can be downloaded here from Segger. The contents are reprinted below:
* (c) SEGGER Microcontroller GmbH & Co. KG *
* The Embedded Experts *
* www.segger.com *
**********************************************************************
-------------------------- END-OF-HEADER -----------------------------
File : NXP_Kinetis_S32_Attach.JLinkScript
Purpose : Script file to skip the device specific connect for the
NXP Kinetis S32 devices, to make an attach possible.
Literature:
[1] J-Link User Guide
*/
/*********************************************************************
*
* Constants (similar to defines)
*
**********************************************************************
*/
/*********************************************************************
*
* Global variables
*
**********************************************************************
*/
/*********************************************************************
*
* Local functions
*
**********************************************************************
*/
/*********************************************************************
*
* Global functions
*
**********************************************************************
*/
/*********************************************************************
*
* InitTarget()
*
* Function description
* If present, called right before performing generic connect sequence.
* Usually used for targets which need a special connect sequence.
* E.g.: TI devices with ICEPick TAP on them where core TAP needs to be enabled via specific ICEPick sequences first
*
* Return value
* >= 0: O.K.
* < 0: Error
*
* Notes
* (1) Must not use high-level API functions like JLINK_MEM_ etc.
* (2) For target interface JTAG, this device has to setup the JTAG chain + JTAG TAP Ids.
*/
int InitTarget(void) {
//
// As this script file is only used for attach purposes, no special handling is required.
// Therefore, we override the default connect handled by the J-Link DLL for this device.
// as it would trigger a reset.
//
return 0;
}
/*************************** end of file ****************************/