PM0051

Glossary

Doc ID 14614 Rev 3

5/27

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Page

A page is a set of blocks. The number of blocks in a page may differ from one device to

another. Refer to Section 2: Memory organization for details on page size according to

the device.

A dedicated option byte can be used to configure by increments of one page the size of

the user boot code. Refer to Section 5: Flash program memory and data EEPROM

comparison for a description of available areas and option bytes according to the

devices.

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Read-while-write (RWW)

The RWW feature provides the ability for the software to perform write operation on

data EEPROM while reading and executing the program memory. Execution time is

therefore optimized. The opposite operation is not allowed: the software cannot read

data memory while writing program memory.

The RWW feature is not available on all STM8 devices. Refer to Table 9 for information

on devices with RWW capability.

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Single wire interface module (SWIM)

The SWIM is a communication protocol managed by hardware in the STM8

microcontrollers. The SWIM main purpose is to provide non intrusive debug capability.

It can also be used to download programs into RAM and execute them. It can also write

(registers or RAM) or read any part of the memory space and jump to any memory

address. The SWIM protocol is used for ICP. It is accessed by providing a specific

sequence on the SWIM pin either during the reset phase or when the device is running

(if allowed by the application).

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System memory

The STM8 system memory is a small ROM accessible when the user software is

executed. It contains the bootloader. The system ROM and the bootloader are not

available on all STM8 devices.

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User boot code area (UBC)

The user boot code area is a write-protected area which contains reset vector, interrupt

vectors, and IAP routine for the device to be able to recover from interrupted or

erroneous IAP programming.

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User mode

The user mode is the standard user software running mode in the STM8. It is entered

either by performing a power-on-reset on the device or by issuing the SWIM SRST

command from a development tool.

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Word

A word is a set of 4 bytes and corresponds to the memory granularity.