ST10F276E datasheet(52/235 Pages) STMICROELECTRONICS

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Bootstrap loader

ST10F276E

52/235

Doc ID 12303 Rev 3

Figure 7.

Hardware provisions to activate the BSL

5.2.5

Memory configuration in bootstrap loader mode

The configuration (that is, the accessibility) of the ST10F276E’s memory areas after reset in

Bootstrap Loader mode differs from the standard case. Pin EA is evaluated when BSL mode

is selected to enable or to not enable the external bus:

●

If EA = 1, the external bus is disabled (BUSACT0 = 0 in BUSCON0 register);

●

If EA = 0, the external bus is enabled (BUSACT0 = 1 in BUSCON0 register).

Moreover, while in BSL mode, accesses to the internal IFLASH area are partially redirected:

●

All code accesses are made from the special Test-Flash seen in the range 00’0000h to

00’01FFFh;

●

User IFLASH is only available for read and write accesses (Test-Flash cannot be read

or written);

●

Write accesses must be made with addresses starting in segment 1 from 01'0000h,

regardless of the value of ROMS1 bit in SYSCON register;

●

Read accesses are made in segment 0 or in segment 1 depending on the ROMS1

value;

●

In BSL mode, by default, ROMS1 = 0, so the first 32 Kbytes of IFlash are mapped in

segment 0.

Example:

In default configuration, to program address 0, the user must put the value 01'0000h in

the FARL and FARH registers but to verify the content of the address 0 a read to

00'0000h must be performed.

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