R01US0079ED0103 Datasheet, PDF (16/66 Pages) Renesas Technology Corp – RENESAS 32-Bit MCU

Data Flash Access Library - Type T01, European Release
Application
Functional Specifications
myRequest
command_enu
bufAddr_u32
idx_u32
cnt_u16
accessType_enu
status_enu
FDL
Figure 4: Usage of the request structure
Details on the request variable structure and its members are given later in section 4.3.3
“r_fdl_request_t”. Please also note that not all structure members are required for all commands. The
individual command descriptions in section 4.5 “Commands” provide the corresponding detailed
information.
3.3 Background Operation
The flash technology provided by Renesas enables the application to write/erase the Data Flash in
parallel to the CPU execution. In order to satisfy the operation in concurrent or distributed systems, the
command execution is divided into two steps:
1. Initiation of the command execution using R_FDL_Execute
2. Processing of the requested command state by using R_FDL_Handler
This approach comes with one important advantage: Command processing can be done centrally at one
place in the target system (normally the idle-loop or the scheduler loop), while the status of the requests
can be polled locally within the requesting tasks.
Please note that R_FDL_Execute only initiates the command execution and returns immediately with the
request-status "busy" after execution of the first internal state (or an error in case the request cannot be
accepted).
The device flash hardware is responsible for executing the operation in the background. The device
hardware operation might be divided into multiple operations, each performed on a separate occasion,
depending on the number of blocks and data items. The first operation is conducted by calling the
R_FDL_Execute function. The second and subsequent operations are triggered by calling the
R_FDL_Handler function. Thus, there is a need to call the R_FDL_Handler function multiple times.
Processing is suspended from the time each separate operation is completed until the next one is
triggered. Therefore, as the time interval between R_FDL_Handler functions call increases, so does the
overall processing time.
An exception to this background operation is R_FDL_CMD_READ command that is executed
synchronously during R_FDL_Execute function.
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User Manual