ADSP-BF535 Blackfin Processor Hardware Reference
3-5
Operating Modes and States
Protected Memory
Additional memory locations can be protected from User mode access. A
Cacheability Protection Lookaside Buffer (CPLB) entry can be created
and enabled, as described in
“Memory Management Unit” on page 6-56
.
Entering User Mode
When coming out of reset, the processor is in Supervisor mode because it
is servicing a reset event. To enter User mode from the Reset state, two
steps must be performed. First, a return address must be loaded into the
RETI
register. Second, an
RTI
must be issued.
Example Code to Enter User Mode Upon Reset
Listing 3-1
provides code for entering User mode from the Reset state.
Listing 3-1. Entering User Mode From Reset
P1.L = START ; /* Point to start of user code */
P1.H = START ;
RETI = P1 ;
RTI ; /* Return from Reset Event */
START : /* Place user code here */
Return Instructions That Invoke User Mode
Table 3-4
provides a summary of return instructions that can be used to
invoke User mode from various processor event service routines. When
these instructions are used in service routines, the value of the return
address must be first stored in the appropriate event
RETx
register. If the
Содержание ADSP-BF535 Blackfin
Страница 80: ...Development Tools 1 26 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 312: ...Working With Memory 6 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 332: ...System Interfaces 7 20 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 360: ...Dynamic Power Management Controller 8 28 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 446: ...Beginning and Ending an SPI Transfer 10 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 522: ...Timing Examples 11 76 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 562: ...IrDA Support 12 40 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 608: ...PCI I O Issues 13 46 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 672: ...References 14 64 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 810: ...SDRAM Controller SDC 18 86 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 811: ...ADSP BF535 Blackfin Processor Hardware Reference 18 87 External Bus Interface Unit...
Страница 812: ...SDRAM Controller SDC 18 88 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 860: ...DMA Bus Debug Registers 20 30 ADSP BF535 Blackfin Processor Hardware Reference...
Страница 908: ...SDRAM Controller External Bus Interface Unit B 36 ADSP BF535 Blackfin Processor Hardware Reference...