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Data Flash Access Library
2.6
Suspension of block oriented commands (erase)
In cases of systems working under critical real-time conditions, immediately
read/write access to the data is a must. In such cases, separate request
variables must be defined for word command accesses and block command
accesses. Both types of access are managed separately on FDL and
requester side.
The suspension and resumption of the running block command (erase) is
managed automatically according to the following rules
- word commands cannot be suspended
- each block command can be suspended by any word command
- User requested block command does always suspend running block
commands of the EEL
- EEL requested block commands cannot suspend running user block
command
In other words:
- word commands have always higher priority than block commands
- user access have always higher priority than EEL (running in background)
The following table shows dependencies between running and requested
commands of EEL or user.
Table 1 Block command suspension rules
command acceptance
requested
command
WCMD
(eel)
WCMD
(user)
BCMD
(eel)
BCMD
(user)
rejected
running command
WCMD
BCMD
(user)
(eel)
suspend/
rejected
resume***
suspend/
rejected
resume
rejected
rejected
rejected
rejected
WCMD
(eel)
rejected
rejected
suspend/
resume
BCMD
(user)
suspend/
resume
suspend/
resume***
rejected
rejected
Agenda:
WCMD = word command
BCMD = block command,
rejected = requested command is rejected
suspend = running block command is suspended
*** when the address of the WCMD refers to the block addressed by BCMD
the WCMD will be rejected too.
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User Manual
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