We are designing a new product based on the STM32H745...we have looked through the documentation but cannot find a description of the hardware interface to add to the PCB for connection with external ST_Link V3 programming module

[Tesla DeLorean]

Same as it has always been...

Use a 20-pin JTAG, 10-pin SWD, or 14-pin STDC14 connector

Want

PA13 SWDIO

PA14 SWCLK

PB3 SWO

NRST

GND

VCC

https://www.st.com/resource/en/user_manual/dm00526767-stlinkv3set-debuggerprogrammer-for-stm8-and-stm32-stmicroelectronics.pdf

[TDK]

You could also consider the ST-Link V3 Mini. Pinouts are in the user manual.

https://www.st.com/en/development-tools/stlink-v3mini.html

https://www.st.com/resource/en/user_manual/dm00555046-stlinkv3mods-and-stlinkv3mini-mini-debuggersprogrammers-for-stm32-stmicroelectronics.pdf