dsp56800e Freescale Semiconductor, Inc, dsp56800e Datasheet - Page 265

• Manufacturer Part Number: dsp56800e
• Description: 16-bit Digital Signal Controller Core
• Manufacturer: Freescale Semiconductor, Inc

; Exact Sequence for Steps 1 through 3
; NOTE: Must Use Assembler Forcing Operator -- Forces 19-bit address
PMEM_TARGET
If a 21-bit target address must be specified for the JMP instruction, the code sequence in Example 8-16
must be used.
; Exact Sequence for Steps 1 through 3
; NOTE: Must Use Assembler Forcing Operator - Forces 21-bit address
PMEM_TARGET
The rules for determining the target address of the JMP instruction that are discussed in Section 8.6.1,
“Entering Data-Memory Execution Mode,” also apply when exiting data-memory execution.
Freescale Semiconductor
Example 8-15. Exiting Data-Memory Execution Mode, 19-Bit Target Address
Example 8-16. Exiting Data-Memory Execution Mode, 21-Bit Target Address
ORG P:BEGIN_X,X:BEGIN_X; (code located in data memory)
.
.
.
BFSET
NOP
NOP
NOP
NOP
NOP
BFCLR
NOP
NOP
JMP
NOP
NOP
NOP
ORG
.
.
.
; Remember to re-enable interrupts
ORG P:BEGIN_X,X:BEGIN_X; (code located in data memory)
.
.
.
BFSET
NOP
NOP
NOP
NOP
NOP
BFCLR
NOP
JMP
NOP
NOP
NOP
ORG
.
.
.
; Remember to re-enable interrupts
#$0300,SR
#$0080,OMR
>PMEM_TARGET ; Jump to 1st instruction in program memory
P:
#$0300,SR
#$0080,OMR
>>PMEM_TARGET; Jump to 1st instruction in program memory
P:
; Disable interrupts
; (wait for interrupts to be disabled)
; (wait for interrupts to be disabled)
; (wait for interrupts to be disabled)
; (wait for interrupts to be disabled)
; (wait for interrupts to be disabled)
; Disable data memory instruction fetches
; (wait for mode to switch)
; (wait for mode to switch)
; (fetched but not executed)
; (fetched but not executed)
; (fetched but not executed)
; (indicates code located in prgm mem)
; Disable interrupts
; (wait for interrupts to be disabled)
; (wait for interrupts to be disabled)
; (wait for interrupts to be disabled)
; (wait for interrupts to be disabled)
; (wait for interrupts to be disabled)
; Disable data memory instruction fetches
; (wait for mode to switch)
; (fetched but not executed)
; (fetched but not executed)
; (fetched but not executed)
; (indicates code located in program memory)
Program Controller
Executing Programs from Data Memory
8-27