How can I prevent the CPU form executing code using ARM Debug Interface (SWD-AP) ?

My target is a Renesas RZ/A1L SOC witch is an Arm Cortex-A9.
I'm only connected via SWD and I'm using the MEM-AP to manipulate the flash controller of the SOC in order to program the external flash.
In fact, it works also while code is executed. The SoC has a display attached and is shows the standard screen with a running clock.
This  uncomfortable

Can anybody tell me witch bit I need to flip to stop the CPU to run code.
I think there must be something ARM specific.
I don't want to alter the reset vector or something to trap the CPU.
I'd like to pause or stop the CPU like the "Stop Button" in a Debugger GUI does.
I have no API or ISE. I use my own code to communicate with the MEM-AP vi SWD.
Can anybody give me a hint.