Pinout And Debug Port Pins - ST STM32F101xx Reference Manual

RM0008
If the debugger host wants to switch to the SW-DP, it must provide a dedicated JTAG
sequence on TMS/TCK (respectively mapped to SWDIO and SWCLK) which disables the
JTAG-DP and enables the SW-DP. This way it is possible to activate the SWDP using only
the SWCLK and SWDIO pins.
This sequence is:
1. Send more than 50 TCK cycles with TMS (SWDIO) =1
2. Send the 16-bit sequence on TMS (SWDIO) = 0111100111100111 (MSB transmitted
first)
3. Send more than 50 TCK cycles with TMS (SWDIO) =1
31.4

Pinout and debug port pins

The STM32F10xxx MCUs are available in various packages with different numbers of
available pins. As a result, some functionality (ETM) related to pin availability may differ
between packages.
Doc ID 13902 Rev 12
Debug support (DBG)
1051/1096