Bootstrap loader
ST10F276E
Figure 7.
Hardware provisions to activate the BSL
%XTERNAL
SIGNAL
.ORMAL BOOT
0ꢉ,ꢌꢇ
0ꢉ,ꢌꢇ
"3,
20ꢉ,ꢌꢇ
ꢆK:ꢀMAXꢌ
20ꢉ,ꢌꢇ
ꢆK:ꢀMAXꢌ
#IRCUIT ꢁ
#IRCUIT ꢀ
'!0'2)ꢉꢉꢈꢁꢇ
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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Doc ID 12303 Rev 3
STMICROELECTRONICS [ ST ]
