RH850 datasheet(22/66 Pages) RENESAS

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Data Flash Access Library - Type T01, European Release

Functional Specifications

R01US0079ED0103

User Manual

3.6 Stand-by and Wake-up functionality

Entering a device power save (stand-by) mode is not allowed, when a Data Flash operation is on-going.

Due to that, especially Data Flash Erase operation can delay entering a power save mode significantly. In

order to allow fast entering of such mode, the functions R_FDL_StandBy and R_FDL_WakeUp have been

introduced. The main functionality of the functions is to suspend a possibly on-going Data Flash Erase or

Write operation (R_FDL_StandBy) and resume it after waking up from power save mode

(R_FDL_WakeUp).

Once started, stand-by processing must always end in stand-by status. Calling the R_FDL_StandBy

does not necessarily immediately suspend any Data Flash operation, as suspend might be delayed by the

device internal hardware or might not be supported at all (only Erase and Write are suspend-able). In this

case, the R_FDL_StandBy function must be called repeatedly until the stand-by status is reached.

Blank Check and Read Data Flash operations are suspendable from software point of view, but the library

will wait for the operation to be finished by hardware while suspend is processed and the result will be

presented after resuming. This wait however is not that important because blank check and read

operations are much faster than erase or write.

In case the FDL is in an idle state (no on-going Data Flash operations), by calling the R_FDL_StandBy

the FDL will immediately enter the Stand-By state. By calling the R_FDL_WakeUp, the FDL will return to

previous state (in this case the idle state).

The following pictures describe the library behaviour in case a stand-by request is issued during FDL

operation:

Figure 10: Stand-By processing on a Data Flash Erase operation

Erase

First block

R_FDL_Execute (Erase 2 blocks)

Start erase block

R_FDL_BUSY

R_FDL_Handler

R_FDL_BUSY

Check (Busy)

…………………………………………………………

User

application

FDL

Data Flash

programming

hardware

Erase

Block 2

Stan

dBy

state

Idle

R_FDL_StandBy

R_FDL_OK

Suspend

R_FDL_WakeUp

R_FDL_OK

Start erasing

interrupted block

R_FDL_Handler

R_FDL_BUSY

Check (Busy)

R_FDL_Handler

R_FDL_OK

Check (Ready)

…………………………………………………………

Erase

Second block

R_FDL_Handler

Start erase block

R_FDL_BUSY

R_FDL_Handler

R_FDL_BUSY

Check (Busy)

Erase

second block

interrupted

RH850 Datasheet(PDF) 22 Page - Renesas Technology Corp

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