TC1784
Program Memory Unit (PMU)
User´s Manual
5-65
V1.1, 2011-05
PMU, V1.47
(e.g. start from external memory or from internal scratchpad memory after bootstrap
execution).
•
If read protection is active and a bootstrap loader is selected by reset configuration,
the execution of bootstrap loader is not suppressed because the Flash is fully
protected with DCF and DDF (see above).
•
If read protection is active and user program is started in internal Flash, the debug
interfaces are totally disabled after reset (controlled by BootROM startup).
•
If read protection is active, only one re-configuration of the instruction cache in PMI
unit is possible after reset. The user shall install his SPR/cache configuration quickly
after reset to lock the configuration and thus the protection; then, data read accesses
to the instruction cache are disabled (because this requires a change of
configuration). Subsequent changes of SPR/cache configuration are only possible, if
the read protection is temporarily disabled with correct passwords.
•
If read protection is active, Flash read accesses are generally
not
disabled in case
of internal start after reset out of the Program Flash (DCF and DDF are cleared
before start of program execution, controlled by BootROM startup). In this case the
user SW in Flash has to handle access restrictions to the Flash by controlling the
Disable Flash Fetch bits in the FCON register.
Examples
:
– Before jumping to external memory or internal RAM, bit DDF is set by user SW in
Flash. In this case, all Flash data accesses are disabled but return to Program
Flash instruction execution is possible (because DCF is not set).
– Before jumping to external memory or internal RAM, bit DDF is set by the user.
DCF is also set by the user directly after jumping to internal or external RAM. Now,
Flash data accesses and return to code fetch from Program Flash are disabled;
return is only possible if the read protection is temporarily disabled (not active)
using the password protected disable command sequence. In this case, bits DCF
and DDF must be cleared by the user before the read protection is resumed,
because otherwise accesses are blocked after resumption.
•
If read protection is active or not, Flash data accesses from dedicated bus masters
others than the CPU/DMI can be separately disabled with the FCON bits DDFDMA
and DDFPCP (bus cycle sources are indicated by tags). These bits cannot be cleared
while read protection is active.
•
A disabled but installed read protection is indicated by RPRODIS=1 in FSR register.
Note: If read protection is active and DCF and DDF are set, not allowed data or
instruction read accesses to Flash result in a LMB bus error (trap) indication. This
has also to be considered for jump predictions. The user has to make sure that the
prediction does not point into the protected Flash.
Installation of read protection is performed with the “Write User Configuration Page”
operation, controlled by the user 0. With this command, user 0 writes the protection
configuration bits RPRO and eventually DFEXPRO, and the two 32-bit keywords into the
UCB0-page 0. Additionally, with a second “Write User Configuration Page” command, a
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 ...