ST10F276 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST10F276' PDF : 229 Pages View PDF
Bootstrap loader
ST10F276
5.4.2
Note:
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.
Entering the CAN bootstrap loader
The ST10F276 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 ST10F276 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
configured in order to send an acknowledge frame. The ST10F276 will not send this
Message Object but the host can request it by sending a remote frame.
The acknowledge frame is the following for the ST10F276:
– Standard identifier = E6h
– DLC = 3h
– Data0 = D5h, that is, generic acknowledge of the ST10 devices
– Data1 = IDCHIP least significant byte
– Data2 = IDCHIP most significant byte
For the ST10F276, IDCHIP = 114Xh.
Two behaviors can be distinguished in ST10 acknowledging to the host. If the host is
behaving according to the CAN protocol, as at the beginning the ST10 CAN is not
configured, the host is alone on the CAN network and does not receive an acknowledge. It
automatically resends the zero frame. As soon as the ST10 CAN is configured, it
acknowledges the zero frame. The “acknowledge frame” with identifier 0xE6 is configured,
but the Transmit Request is not set. The host can request this frame to be sent and therefore
obtains the IDCHIP by sending a remote frame.
Hint: As the IDCHIP is sent in the acknowledge frame, Flash programming software now
can immediately identify the exact type of device to be programmed.
58/229
Share Link: 
