Development Tools; Single Wire Interface Module (Swim); Swim Overview; Swim Connector Pins - ST STM8S Getting Started

Development tools

8 Development tools
Development tools for STM8S and STM8AF microcontrollers include the STice emulation
system supported by a complete software tool package including C compiler, assembler and
integrated development environment with high-level language debugger.
8.1

Single wire interface module (SWIM)

8.1.1

SWIM overview

In-circuit debugging mode or in-circuit programming mode are managed through a single
wire hardware interface based on an open-drain line, featuring ultra fast memory
programming. Coupled with an in-circuit debugging module, the SWIM also offers a
non-intrusive read/write to RAM and peripherals. This makes the in-circuit debugger
extremely powerful and close in performance to a full-featured emulator.
The SWIM pin can be used as a standard I/O (with 8 mA capability) which has some
restrictions if the user wants to use it for debugging. The most secure way to use it is to
provide a strap option on the PCB. Refer to the STM8 SWIM communication protocol and
debug module user manual UM0470, available on
details.
8.1.2

SWIM connector pins

The SWIM connector pins consist of four pins, as described in
20/40

Figure 11. Debug system block diagram

100 kHz Osc
SWIM entry
DBG
Comm
CMD
layer decode
Internal RC
Table 2. SWIM connector pins
Pin number
Pin 1
Pin 2
Pin 3
Pin 4
AN2752 Rev 6
www.st.com for more SWIM protocol
Peripheral
STM8
DM
core
Table
Pin name
V
DD
SWIM pin
V
SS
Reset
AN2752
RAM
NVM
2.