Hi David,
I have the ST-LINK V2/ISOL.
At least these 2 conditions must be met:
1. You also need to connect the ST-LINK-V2 RESET pin to the target MCU RESET pin !
Make sure to have all connections in user manual UM1075, par. 3.1.3 "SWIM signals and connections", table 2.
2. The ST-LINK-V2 RESET pin must be ABLE to pull the MCU-RESET pin low enough.
So if you drive the target MCU-RESET pin by a push-pull driver or your pull-up resistor is very low,
the ST-LINK-V2 RESET pin driver might not reach a sufficent low level to cause a MCU reset.
The ST-LINK-V2 RESET pin is an input and an open drain output with a 680 Ohm pull-up.
Best use a wired-or aproach on your target board.
Hope this helps,
John
