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TC1784
BootROM Content
User´s Manual
7-3
V1.1, 2011-05
BOOT_TC1784B, V1.21R12
– SPRAM upon a Bootstrap Loader mode
•
the user code configures and activates the EBU
•
a jump is performed to the desired location in External memory
7.4
Bootstrap Loading
Different Bootstrap Loader routines are used in these modes to download code/data into
the Instruction Scratchpad Memory SPRAM (PMI)
The selected Bootstrap Loader is executed only if the SSW-flag “Reset Configuration
Updated” is set (refer to
). This is to avoid multiple executions of the
Bootstrap Loader and to start directly the code already downloaded after some -
intended to be “application only” - reset events, for example after a Watchdog Timer
reset which has been configured as application reset.
The supported Bootloader selections are:
•
ASC Bootloader - ASC communication protocol via ASC pins, as follows:
– receive pin RxD at Pin 0 Port 3 (P3.0)
– transmit pin TxD at Pin 1 Port 3 (P3.1)
•
Generic Bootloader via CAN pins - the communication protocol is automatically
selected by the SSW between ASC and CAN, the pins are used as follows:
– receive pin RxD at Pin 12 Port 3 (P3.12)
– transmit pin TxD at Pin 13 Port 3 (P3.13)
After downloading (in case) the code, the User Start Address STADD is set to the
beginning of PMI Scratchpad RAM at D400’0000
H
.
7.4.1
Common Procedures for all Bootloaders
The first such a common procedure is to reconfigure the clock system in case the last
reset is a Power-on. This reconfiguration switches from the initial PLL Freerunning mode
(VCO base frequency) to Prescaler Mode with F
FPI
:F
OSC
=1:2.
Therefore the FPI-peripherals (including MultiCAN and ASC modules) run at half the
frequency of an external crystal which must be connected between XTAL1/XTAL2 pins
if a Bootloader mode will be selected upon Power-on. This 1:2 relation must be taken
into account when selecting the host speed for downloading. For example, when using
the MultiCAN bootstrap loader F
OSC
should be greater or equal to 20 MHz for a baud rate
of 1 Mbit/s.
Attention: This clock-switch to external oscillator upon Power-on is overwritten
by a switch back to PLL freerunning mode at the end of SSW .
Therefore if it is desired after downloading to continue communication
with the same baudrate, the user code must first reinstall:
- PLL prescaler mode (SCU_PLLCON0.VCOBYP:=0) and
- K1 divider 1:1 (SCU_PLLCON1.KDIV:=00
H
).
Summary of Contents for TC1784
Page 1: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Page 3: ...User s Manual V1 1 2011 05 Microcontrollers TC1784 32 Bit Single Chip Microcontroller ...
Page 950: ...TC1784 Direct Memory Access Controller DMA User s Manual 11 132 V1 1 2011 05 DMA V3 03 ...
Page 1949: ...TC1784 General Purpose Timer Array GPTA v5 User s Manual 21 297 V1 1 2011 05 GPTA v5 V1 14 ...
Page 2350: ...w w w i n f i n e o n c o m Published by Infineon Technologies AG Doc_Number ...