Bootstrap Loader (Bsl) - Infineon Technologies TC1796 User Manual

4.4

Bootstrap Loader (BSL)

The bootstrap loader (BSL) is a software part which is integrated in the TC1796 Boot
ROM. The BSL provides a mechanism to load a program code via a serial interface (ASC
or CAN) into the scratchpad RAM (SPRAM) of the PMI. After loading of the code, the
BSL jumps directly to address D400 0000
and begins executing the program code that has been loaded. The BSL automatically
calculates the baud rate of the serial data streams.
Table 4-5 shows the three BSL modes with its parameters.
Table 4-5 Bootstrap Loader Selections
Bootstrap Loader Mode
Bootstrap Loader Mode 1 (BSL1):
ASC Boot via ASC0 Pins
Bootstrap Loader Mode 2 (BSL2):
CAN Boot
Bootstrap Loader Mode 3 (BSL3):
ASC Boot via CAN Pins
1) The bootstrap loader mode selections in alternate boot modes see
With the low-to-high signal transition of the hardware reset signal HDRST or the power-
on reset signal PORST, the input pins BRKIN and HWCFG[3:0] of the TC1796 are
latched. If one of the latched BRKIN/HWCFG[3:0] signal combination of
detected, the bootstrap loader is started and the selected bootstrap loader mode is
entered.
The bootstrap loader can also be started by a software reset. For this purpose, bit
RST_REQ.SWBRKIN and bit field RST_REQ.SWCFG must be loaded with the
corresponding BRKIN/HWCFG[3:0] code, and bit RST_REQ.SWBOOT must be set (see
also RST_REQ register description at
When a boot option for a bootstrap loader mode is detected, the TC1796 jumps to
address DFFF FFFC
of the bootstrap loader, the Watchdog Timer interrupts and NMI interrupts are disabled.
User's Manual
Reset, V2.0
BRKIN
1
Page
which is the last word address of the Boot ROM. During execution
H
System Units (Vol. 1 of 2)
Reset and Boot Operation
(start address of the PMI scratchpad RAM)
H
1)
Selection
HWCFG
[3:0]
0000
B
0001
B
1111
B
Table
4-5).
4-20
TC1796
Associated I/O Lines
Receive Transmit
P5.0 / P5.1 /
RXD0A TXD0A
P6.8 / P6.9 /
RXDCAN0 TXDCAN0
P6.8 / P6.9 /
RXD0B TXD0B
4-3.
Table 4-5
V2.0, 2007-07
is