Vims Software Remarks - Texas Instruments SimpleLink CC2620 Technical Reference Manual

VIMS Software Remarks

7.2 VIMS Software Remarks
When the flash is programmed or updated, or when the VIMS domain is entering power down special care
must be taken from the software side.
The following remarks are automatically taken care of when using in-built ROM functions and the standard
API functions. However, custom code must take the following remarks into account.
7.2.1 Flash Program or Update
Before updating the flash, the VIMS cache and line buffers must be invalidated and flushed to prevent old
data or instructions from being fetched from the cache or line buffers after a flash program or update.
Hence, the VIMS mode must be set to GPRAM or OFF mode before programming, and both VIMS flash
line buffers must be set to disabled.
7.2.2 VIMS Retention
The VIMS domain can be kept in retention, if needed, when the domain is entering power down. The
retention control has the option to specify which memories (internal TAG RAM or cache RAM) are kept in
retention together with VIMS logic.
NOTE: If the whole MCU domain is powered off, the VIMS domain does not support retention.
Table 7-1 specifies the valid retention combination for VIMS memory.
Mode
TAG-RAM
1 No
2 No
3 Yes
7.2.2.1 Mode 1
Mode 1 is intended for use when the system is in off mode, cache mode.
When the cache is enabled (in cache mode), software must manually change the VIMS mode to off mode
before entering retention. When the system is taken out of retention, software must put VIMS back into
either cache mode, which invalidates the cache memories (see
Mode 1 can also be used when the system is in GPRAM mode, but software must take into account that
the data in the GPRAM is lost when the system is set in retention.
538
Versatile Instruction Memory System (VIMS)
Table 7-1. Valid Retention Combination for VIMS Memory
Retention Enabled
CACHE-RAM
No
Yes
Yes
Figure 7-7. Software Precautions With No RAM Retention
Mode 1
ENABLED
SPLIT
pwr down
INIT
SPLIT
Copyright © 2015, Texas Instruments Incorporated
VIMS Logic
Yes
Yes
Yes
Figure
or
OFF
TAG and
cache
memory are
corrupted
OFF
INIT
ENABLED
SWCU117C – February 2015 – Revised September 2015
Comment
Software must compensate for loss of data
in RAMs
Works in GPRAM mode without software
intervention
7-7).
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