Workaround
Ensure that DMA accesses to the affected modules occur only when the modules are
not in operation. For example with the MPY module, ensure that the MPY operation is
completed before triggering a DMA access to the MPY module.
EEM8
EEM Module
Category
Debug
Function
Debugger stops responding when using the DMA
Description
In repeated transfer mode, the DMA automatically reloads the size counter (DMAxSZ)
once a transfer is complete and immediately continues to execute the next transfer unless
the DMA Enable bit (DMAEN) has been previously cleared. In burst-block transfer mode,
DMA block transfers are interleaved with CPU activity 80/20% - of ten CPU cycles, eight
are allocated to a block transfer and two are allocated for the CPU.
Because the JTAG system must wait for the CPU bus to be clear to halt the device, it can
only do so when two conditions are met:
- Three clock cycles after any DMA transfer, the DMA is no longer requesting the bus.
and
- The CPU is not requesting the bus.
Therefore, if the DMA is configured to operate in the repeat burst-block transfer mode,
and a breakpoint is set between the line of code that triggers the DMA transfers and the
line that clears the DMAEN bit, the DMA always requests the bus and the JTAG system
never gains control of the device.
Workaround
When operating the DMA in repeat burst-block transfer mode, set breakpoint(s) only when
the DMA transfers are not active (before the start or after the end of the DMA transfers).
EEM17
EEM Module
Category
Debug
Function
Wrong Breakpoint halt after executing Flash Erase/Write instructions
Description
Hardware breakpoints or Conditional Address triggered breakpoints on instructions that
follow Flash Erase/Write instructions, stops the debugger at the actual Flash Erase/Write
instruction even though the flash erase/write operation has already been executed. The
hardware/conditional address triggered breakpoints that are placed on either the next two
single opcode instructions OR the next double opcode instruction that follows the Flash
Erase/Write instruction are affected by this erratum.
Workaround
None. Use other conditional/advanced triggered breakpoints to halt the debugger right
after Flash erase/write instructions.
Note
This erratum affects debug mode only.
EEM19
EEM Module
Category
Debug
Function
DMA may corrupt data in debug mode
Advisory Descriptions
SLAZ647S – FEBRUARY 2015 – REVISED MAY 2021
MSP430F6735A Microcontroller
13
Copyright © 2021 Texas Instruments Incorporated
