The RMxxL series features a so called ICEPick which requires a special connect sequence. This sequence is executed by default by the J-Link DLL if the proper device (e.g. RM57L843ZWT) is selected. How to select the correct device: https://wiki.segger.com/Selecting_the_correct_device
Note: By default, the J-Link DLL assumes one RMxxL device in the JTAG-chain (TDI -> RMxxL -> TDO).
If a different JTAG-chain is used, a adapted J-Link Script File is required which contains the updated configuration. Please find below two script files for a setup where two RMxxL devices are chained in a JTAG-chain (TDI -> RMxxL (#0) -> RMxxL (#1) -> TDO).
Note: If your JTAG-chain configuration differs from the default and the above one, please get in contact with SEGGER.
RAM initialization on connect
The RM4xL and RM5xL device series comes with an ECC protected RAM. To make sure that no ECC errors are generated when reading from the ECC protected RAM region, the J-Link DLL has to initialize this region before reading it in order to make sure that the ECC is valid. Prior the initialization is issued, a reset of the MCU is performed in order to bring the device into a proper state and to make sure that hardware units like for example DMAs are halted during the RAM init. The actual ECC init is performed by using the Memory Hardware Initialization of the MCU.
Whereas this RAM init is required for most setups, there are some setups where this could cause issues (e.g. when attaching to a running session). In order to prevent the J-Link DLL from executing the RAM initialization, an command string must be passed to the J-Link DLL. This can be done by using a J-Link script file. Further information regarding the J-Link script file can be found in the J-Link User Manual (UM08001).
Please note, that the script file has been tested with version V6.12b of the J-Link software and documentation package