Programming STM8 Flash microcontrollers

PM0212

18/22

Doc ID 022351 Rev 2

4.6.1

ICP methods

The in-circuit programming (ICP) method is used to update the content of Flash program

memory and data EEPROM.

The programming interface for STM8 devices is the SWIM (Single Wire Interface Module). It

is used to communicate with an external programming device connected via a cable.

See STM8 SWIM communication protocol and debug module user manual (UM0470) for

more details on the SWIM mode entry and SWIM protocol.

When using the SWIM protocol, two methods can be used:

SWIM active (ICP

mode)

Readout

protection

enabled

Interrupt vectors except for TRAP

P

TRAP

P

Proprietary code area (PCODE)

P(4)

User boot code area (UBC)

P

Main program

P

Data EEPROM area (DATA)

P

Option bytes

(6)

Readout

protection

disabled

Interrupt vectors except for TRAP

R/W/E

TRAP

R/W/E

Proprietary code area (PCODE)

R/E(4)

User boot code area (UBC)

R/E(5)

Main program

Data EEPROM area (DATA)

R/W(3)

Option bytes

R/W

1.

R/W/E = Read; Write and Execute;

R/E = Read and Execute (write operation forbidden);

R = Read (write and execute operations forbidden);

P = the area cannot be accessed (read, execute and write operations forbidden);

2.

When no UBC area has been defined, the interrupt vectors, except for TRAP, can be modified in user

/IAP mode.

3.

The data memory is write protected (locked) until the correct MASS key is written in the

FLASH_DUKR. It is possible to lock the memory again by resetting the DUL bit in the IAPSR register.

If wrong keys are provided, another key program sequence can be performed without resetting the

device.

4.

The PCODE area can be read and executed only in privileged mode through the TRAP vector. The

PCODE cannot be directly accessed through the SWIM.

5.

To program the UBC area the application must first clear the UBC option byte.

6.

When ROP is removed, the whole memory is erased, including option bytes.

7.

The Flash program memory is write protected (locked) until the correct MASS key is written in the

FLASH_PUKR. It is possible to lock the memory again by resetting the PUL bit in the FLASH_IAPSR

register. If wrong keys are provided, the device must be reset and new keys programmed.

Table 5.

Memory access versus programming method (continued)

Mode

ROP

Memory Area

Access