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Reset
InitBoot
SelectBootMode
Select jump
to M0 SARAM
ExitBoot
Jump to
0x00 0000
Execution
continues
Reset
InitBoot
SelectBootMode
Select jump
to OTP
ExitBoot
Jump to
0x3D 7800
Execute
preprogrammed
OTP code
Bootloader Modes
Figure 2-4. Flow Diagram of Jump to M0 SARAM
•
Jump to OTP memory
In this mode, the boot ROM software will configure the device for 28x operation and then branch
directly to at 0x3D 7800; the first address in the OTP memory block.
On ROM devices, the boot-to-OTP option jumps to address 0x3D 7800 in ROM. On RAM devices, the
boot-to-OTP option jumps to reserved memory and should not be used.
Figure 2-5. Flow Diagram of Jump-to-OTP Memory
The following boot modes call a boot load routine that loads a data stream from the peripheral into
memory:
•
Standard serial boot mode (SCI-A)
In this mode, the boot ROM will load code to be executed into on-chip memory via the SCI-A port.
•
SPI EEPROM boot mode (SPI-A)
In this mode, the boot ROM will load code and data into on-chip memory from an external EEPROM
via the SPI-A port.
•
I
2
C-A boot mode (I
2
C-A)
In this mode, the boot ROM will load code and data into on-chip memory from an external EEPROM at
address 0x50 on the I
2
C-A bus. The EEPROM must adhere to conventional I
2
C EEPROM protocol with
a 16-bit base address architecture.
•
eCAN Boot Mode (eCAN-A)
In this mode, the eCAN-A peripheral is used to transfer data and code into the on-chip memory using
eCAN-A mailbox 1. The transfer is an 8-bit data stream with two 8-bit values being transferred during
each communication. On devices that do not have an eCAN-A peripheral, this mode is reserved and
should not be used.
•
Boot from GPIO Port (Parallel Boot from GPIO0-GPIO15)
In this mode, the boot ROM uses GPIO port A pins GPIO0-GPIO15 to load code and data from an
external source. This mode supports both 8-bit and 16-bit data streams. Since this mode requires a
number of GPIO pins, it is typically used to download code for flash programming when the device is
connected to a platform explicitly for flash programming and not a target board.
SPRU722C – November 2004 – Revised October 2006
Bootloader Features
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