ST10F276E datasheet(59/235 Pages) STMICROELECTRONICS

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ST10F276E

Bootstrap loader

Doc ID 12303 Rev 3

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Figure 11.

CAN bootstrap loader sequence

BSL initialization time, > 1ms @ fCPU = 40 MHz

Zero frame (CAN message: standard ID = 0, DLC = 0), sent by host

CAN message (standard ID = E6h, DLC = 3, Data0 = D5h, Data1-Data2 = IDCHIP_low-high), sent by

ST10F276E on request

128 bytes of code / data, sent by host

Caution: CAN1_TxD is only driven a certain time after reception of the zero byte (1.3ms @ fCPU = 40 MHz).

Internal Boot ROM / Test-Flash

The Bootstrap Loader can load

●

the complete application software into ROM-less systems,

●

temporary software into complete systems for testing or calibration,

●

a programming routine for Flash devices.

The BSL mechanism may be used for standard system start-up as well as for only special

occasions like system maintenance (firmware update) or end-of-line programming or

testing.

5.4.2

Entering the CAN bootstrap loader

The ST10F276E enters BSL mode if pin P0L.4 is sampled low at the end of a hardware

reset. In this case, the built-in bootstrap loader is activated independently of the selected

bus mode. The bootstrap loader code is stored in a special Test-Flash; no part of the

standard mask ROM or Flash memory area is required for this.

After entering BSL mode and the respective initialization, the ST10F276E scans the

CAN1_TxD line to receive the following initialization frame:

●

Standard identifier = 0h

●

DLC = 0h

As all the bits to be transmitted are dominant bits, a succession of 5 dominant bits and 1

stuff bit on the CAN network is used. From the duration of this frame, it calculates the

corresponding baud rate factor with respect to the current CPU clock, initializes the CAN1

interface accordingly, switches pin CAN1_TxD to output and enables the CAN1 interface to

take part in the network communication. Using this baud rate, a Message Object is

ST10F276E Datasheet(PDF) 59 Page - STMicroelectronics