ST10F276 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST10F276' PDF : 229 Pages View PDF
Bootstrap loader
ST10F276
5.6.4
5.6.5
Note:
5.6.6
Note:
ST10 configuration in alternate boot mode
When the ST10F276 enters BSL mode via CAN, the configuration shown in Table 35 is
automatically set (values that deviate from the normal reset values are marked in bold).
Table 35. ST10 configuration in alternate boot mode
Function or register
Access
Notes
Watchdog timer
Register SYSCON
Disabled
0404H(1)
XPEN bit set
Context pointer CP
Register STKUN
Stack pointer SP
Register STKOV
Register BUSCON0
FA00H
FA00H
FA40H
FC00H
acc. to startup config.(2)
XPERCON
002DH
XRAM1-2, XFlash, CAN1 enabled
1. In Bootstrap modes (standard or alternate) ROMEN, bit 10 of SYSCON, is always set regardless of EA pin
level. BYTDIS, bit 9 of SYSCON, is set according to data bus width selection via Port0 configuration.
2. BUSCON0 is initialized with 0000h, external bus disabled, if pin EA is high during reset. If pin EA is low
during reset, BUSACT0, bit 10, and ALECTL0, bit 9, are set enabling the external bus with lengthened ALE
signal. BTYP field, bit 7 and 6, is set according to Port0 configuration.
Even if the internal IFLASH is enabled, a code cannot be executed from it.
As the XFlash is needed, XPERCON register is configured by the ABM loader code and bit
XPEN of SYSCON is set. However, as long as the EINIT instruction is not executed (and it is
not in the bootstrap loader code), the settings can be modified. To do this, perform the
following steps:
● Copy in DPRAM a function that will
– disable the XPeripherals by clearing XPEN in SYSCON register,
– enabled the needed XPeripherals by writing the correct value in XPERCON
register,
– set XPEN bit in SYSCON,
– return to calling address.
● Call the function from XFlash
The changing of the XPERCON value cannot be executed from the XFlash because the
XFlash is disabled by the clearing of XPEN bit in SYSCON.
Watchdog
As for standard boot, the Watchdog timer remains disabled during Alternate Boot Mode. In
case a Watchdog reset occurs, a software reset is generated.
See note from Section 5.2.7 concerning software reset.
Exiting alternate boot mode
Once the ABM mode is entered, it can be exited only with a software or hardware reset.
See note from Section 5.2.7 concerning software reset.
66/229
Share Link: 
