2. A false condition on the jump breaks out of the loop
In such cases the trace buffer incorrectly displays the first instruction of the loop as the
instruction that is executed immediately after exiting the loop.
Example:
Actual Code:
mov #4,R4
LABEL mov #1,R5
dec R4
jnz LABEL
mov #2,R6
nop
State Storage Window Displays:
LABEL mov #1,R5
dec R4
jnz LABEL
mov #1,R5
nop
Workaround
None
Note: This erratum affects the trace buffer display only. It does not affect code execution in
debugger or free run mode
CPU40
CPU Module
Category
Compiler-Fixed
Function
PC is corrupted when executing jump/conditional jump instruction that is followed by
instruction with PC as destination register or a data section
Description
If the value at the memory location immediately following a jump/conditional jump
instruction is 0X40h or 0X50h (where X = don't care), which could either be an instruction
opcode (for instructions like RRCM, RRAM, RLAM, RRUM) with PC as destination
register or a data section (const data in flash memory or data variable in
RAM), then the PC value is auto-incremented by 2 after the jump instruction is executed;
therefore, branching to a wrong address location in code and leading to wrong program
execution.
For example, a conditional jump instruction followed by data section (0140h).
@0x8012 Loop DEC.W R6
@0x8014 DEC.W R7
@0x8016 JNZ Loop
@0x8018 Value1 DW 0140h
Workaround
In assembly, insert a NOP between the jump/conditional jump instruction and program
code with instruction that contains PC as destination register or the data section.
Refer to the table below for compiler-specific fix implementation information.
Advisory Descriptions
SLAZ476AD – DECEMBER 2012 – REVISED MAY 2021
MSP430F6777 Microcontroller
11
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