![Infineon Technologies TC1796 Скачать руководство пользователя страница 208](http://html1.mh-extra.com/html/infineon-technologies/tc1796/tc1796_user-manual_2055437208.webp)
TC1796
System Units (Vol. 1 of 2)
Reset and Boot Operation
User’s Manual
4-16
V2.0, 2007-07
Reset, V2.0
4.3
Boot ROM
The internal 16 Kbyte Boot ROM (BROM) has two parts:
•
8 Kbyte reserved for boot code (Boot ROM)
•
8 Kbyte reserved for factory test routines (Test ROM).
Note: The expression “Boot ROM” in the text always refers to the 8 Kbyte boot code part
of the BROM.
4.3.1
Addressing
As the original architectural position of the BROM is on the FPI Bus and the boot vector
to the Boot ROM is hardwired in the CPU to this location. The internal BROM in the
TC1796 is visible from the PMI side at three different locations, as can be seen in the
memory map:
•
In segment 8 (cached) starting at location 8FFF C000
H
•
In segment 10 (non-cached) starting at location AFFF C000
H
•
In segment 13 (FPI space) starting at location DFFF C000
H
.
From DMI side, the internal ROM is not visible in segment 13. Accesses to these
addresses will be routed to the FPI Bus and will cause a bus error.
The hardware-controlled start address after reset is address DFFF FFFC
H
. At this
location (within the BROM), a jump to start address AFFF F180
H
is programmed to
guarantee continuation of start program execution after reset.
Because the reset start address is fixed, the Boot ROM is mapped to the upper part of
the internal BROM, at locations ..E000 - ..FFFF
H
, and the TestROM is mapped to the
lower part of internal BROM (..C000 - ..DFFF
H
).
4.3.2
Program Structure
The different sections of the 8 Kbyte Boot ROM provide the following functionalities.
Startup Procedure
The startup procedure is the main control program in the Boot ROM which is always
started after every reset operation. It initializes the chip, checks the hardware or software
configuration selections, and branches to the corresponding boot routines. From a user
point of view, the startup procedure lengthens the reset time of the TC1796.
The startup procedure is responsible for the correct initialization of the on-chip
resources. For example, the startup procedure monitors the Flash ramp-up phase and
waits until the Flash memories are ready to be used. The startup procedure further
controls the Flash read protection, initializes SRAM redundancy settings, and copies the
unique chip identifier from Flash into the LDRAM memory.