SLAZ337AA December   2012  – September 2021 MSP430F6659

 

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6.9 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.

IDE/Compiler Version Number Notes
IAR Embedded Workbench IAR EW430 v5.51 or later For the command line version add the following information Compiler: --hw_workaround=CPU40 Assembler:-v1
TI MSP430 Compiler Tools (Code Composer Studio) v4.0.x or later User is required to add the compiler or assembler flag option below. --silicon_errata=CPU40
MSP430 GNU Compiler (MSP430-GCC) Not affected