Datasheet

STM8S207xx, STM8S208xx Product overview
Doc ID 14733 Rev 12 15/103
The size of the UBC is programmable through the UBC option byte (Table 13.), in
increments of 1 page (512 bytes) by programming the UBC option byte in ICP mode.
This divides the program memory into two areas:
● Main program memory: Up to 128 Kbytes minus UBC
● User-specific boot code (UBC): Configurable up to 128 Kbytes
The UBC area remains write-protected during in-application programming. This means that
the MASS keys do not unlock the UBC area. It protects the memory used to store the boot
program, specific code libraries, reset and interrupt vectors, the reset routine and usually the
IAP and communication routines.
Figure 2. Flash memory organisation
Read-out protection (ROP)
The read-out protection blocks reading and writing the Flash program memory and data
EEPROM memory in ICP mode (and debug mode). Once the read-out protection is
activated, any attempt to toggle its status triggers a global erase of the program and data
memory. Even if no protection can be considered as totally unbreakable, the feature
provides a very high level of protection for a general purpose microcontroller.
Programmable area from 1 Kbyte
Data
UBC area
Program memory area
Data memory area (2 Kbytes)
(2 first pages) up to 128 Kbytes
EEPROM
Remains write protected during IAP
memory
128 Kbytes
Flash
Up to
Write access possible for IAP
program
memory
(1 page steps)
Option bytes