st10f273m STMicroelectronics, st10f273m Datasheet - Page 48

• Manufacturer Part Number: st10f273m
• Description: 16-bit Mcu With 512 Kbyte Flash Memory And 36 Kbyte Ram
• Manufacturer: STMicroelectronics

Bootstrap loader
6
6.1
6.2
Caution:
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Bootstrap loader
The ST10F273M implements Boot capabilities in order to:
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Selection among user-code, standard or selective bootstrap
The boot modes are triggered with a special combination set on Port0L[5...4]. Those
signals, as other configuration signals, are latched on the rising edge of RSTIN pin.
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Table 27.
Standard bootstrap loader
After entering the standard BSL mode and the respective initialization, the ST10F273M
scans the RxD0 line and the CAN1_RxD line to receive either a valid dominant bit from the
CAN interface or a start condition from the UART line.
Start condition on UART RxD: ST10F273M starts standard bootstrap loader. This
bootstrap loader is identical to that of other ST10 devices (example: ST10F269, ST10F168).
Valid dominant bit on CAN1 RxD: ST10F273M start bootstrapping via CAN1.
As both UART_RxD and CAN1_RxD lines are polled to detect a start of communication,
ensure a stable level on the unused channel by adding a pull-up resistor.
.
P0.5
1
1
0
0
Support bootstrap via UART or bootstrap via CAN for the standard bootstrap
Support a Selective Bootstrap Loader, to manage the bootstrap sequence in a different
way
Decoding of reset configuration (P0L.5 = 1, P0L.4 = 1) selects the normal mode (also
called User mode) and selects the user Flash to be mapped from address 00’0000h.
Decoding of reset configuration (P0L.5 = 1, P0L.4 = 0) selects ST10 standard bootstrap
mode (Test-Flash is active and overlaps user Flash for code fetches from address
00'0000h; user Flash is active and available for read accesses).
Decoding of reset configuration (P0L.5 = 0, P0L.4 = 1) activates additional verifications
to select which bootstrap software to execute:
–
–
if the User mode signature in the User Flash is programmed correctly, then a
software reset sequence is selected and the User code is executed;
if the User mode signature is not programmed correctly in the user Flash, then the
User key location is read again. Its value determines which communication
channel will be enabled for bootstrapping.
P0.4
ST10F273M boot mode selection
1
0
1
0
User mode: User Flash mapped at 00’0000h
Standard Bootstrap Loader: User Flash mapped from 00’0000h, code fetches
redirected to Test-Flash at 00’0000h
Selective Boot mode: User Flash mapped from 00’0000h, code fetches
redirected to Test-Flash at 00’0000h (different sequence execution compared to
Standard Bootstrap Loader)
Reserved
ST10 decoding
ST10F273M