ST10F276E datasheet(51/235 Pages) STMICROELECTRONICS

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ST10F276E

Bootstrap loader

Doc ID 12303 Rev 3

51/235

5.2.3

Booting steps

As Figure 6 shows, booting ST10F276E with the boot loader code occurs in a minimum of

four steps:

The ST10F276E is reset with P0L.4 low.

The internal new bootstrap code runs on the ST10 and a first level user code is

downloaded from the external device, via the selected serial link (UART0 or CAN1).

The bootstrap code is contained in the ST10F276E Test-Flash and is automatically run

when ST10F276E is reset with P0L.4 low. After loading a preselected number of bytes,

ST10F276E begins executing the downloaded program.

The first level user code runs on ST10F276E. Typically, this first level user code is

another loader that downloads the application software into the ST10F276E.

The loaded application software is now running.

Figure 6.

Booting steps for ST10F276E

5.2.4

Hardware to activate BSL

The hardware that activates the BSL during reset may be a simple pull-down resistor on

P0L.4 for systems that use this feature at every hardware reset. For systems that use the

bootstrap loader only temporarily, it may be preferable to use a switchable solution (via

jumper or an external signal).

Note:

CAN alternate function on Port4 lines is not activated if the user has selected eight address

segments (Port4 pins have three functions: I/O port, address segment and CAN). Boot via

CAN requires that four or less address segments are selected.

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