STM8S105C4 Datasheet, PDF (14/121 Pages) STMicroelectronics – Extended instruction set

Product overview
STM8S105x4/6
4.2
Single wire interface module (SWIM) and debug module (DM)
The single wire interface module and debug module permits non-intrusive, real-time in-
circuit debugging and fast memory programming.
SWIM
Single wire interface module for direct access to the debug module and memory
programming. The interface can be activated in all device operation modes. The maximum
data transmission speed is 145 bytes/ms.
Debug module
The non-intrusive debugging module features a performance close to a full-featured
emulator. Beside memory and peripherals, also CPU operation can be monitored in real-
time by means of shadow registers.
 R/W to RAM and peripheral registers in real-time
 R/W access to all resources by stalling the CPU
 Breakpoints on all program-memory instructions (software breakpoints)
 Two advanced breakpoints, 23 predefined configurations
4.3
Interrupt controller
 Nested interrupts with three software priority levels,
 32 interrupt vectors with hardware priority,
 Up to 37 external interrupts on 6 vectors including TLI,
 Trap and reset interrupts
4.4
Flash program and data EEPROM memory
 Up to 32 Kbyte of Flash program single voltage Flash memory,
 Up to 1 Kbyte true data EEPROM,
 Read while write: writing in data memory possible while executing code in program
memory,
 User option byte area.
Write protection (WP)
Write protection of Flash program memory and data EEPROM is provided to avoid
unintentional overwriting of memory that could result from a user software malfunction.
There are two levels of write protection. The first level is known as MASS (memory access
security system). MASS is always enabled and protects the main Flash program memory,
data EEPROM and option bytes.
To perform in-application programming (IAP), this write protection can be removed by
writing a MASS key sequence in a control register. This allows the application to write to
data EEPROM, modify the contents of main program memory or the device option bytes.
A second level of write protection, can be enabled to further protect a specific area of
memory known as UBC (user boot code). Refer to the figure below.
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