STM32CubeWBA: Flash management

Coming soon

1. Introduction

Flash management proposes a simple interface to the upper layers to execute operations in FLASH. It manages synchronization between flash operations and the RF activity. Thus, users do not have to bother with RF timing and flash operations.

2. Features

2.1. Concepts

The flash management is a multi-layer organization and rely on different concepts. Among these concepts, here are the most important ones:

• Organization:

Flash management is based upon a 5 layers distribution composed by:

Simple NVM Arbiter

Specific flash interface that emulates the behavior of multiple NVMs.

Flash manager

Main user interface for flash operation (Flash write, flash erase, etc.).

RF Timing synchro

Module that realizes synchronization between BLE LL and Flash operations by activating or deactivating the dedicated flash control status.

Flash Driver

Low level driver abstraction layer. Controlled by the flash control statuses.

HAL Flash

Low level driver that interacts directly with the Flash HW.

• Asynchronous Operations:

The whole flash operations are either executed via the Flash Manager interface or via the Simple NVM Arbiter interface. Both work on an asynchronous behavior, which means that the user is requesting operations to be performed and is notified later on, once the operation is over.

However, since the operation is asynchronous, during write operation, the user shall hold his buffer allocation as long as the write operation is not done. In case of a content change in this buffer, the user shall restart a brand-new flash operation.

• Synchronous flash access with RF:

Flash operations achieved with Flash manager or Simple NVM Arbiter are synchronized with RF activity. Meaning that flash operations are achieved only during free RF activity time slot.

This feature is transparent to the user and is fully handled by the Flash manager or the Simple NVM Arbiter. Therefore, the user does not have to bother with RF and Flash synchro. This is all, already, managed.

• Flash Access:

In this Flash management implementation, the Flash access is protected at two distinct levels:

Flash semaphore

A semaphore is required to share the flash interface between several SW modules. The owner of the semaphore is the only one that can request flash operations. The semaphore is attributed to the first requester and released once its operation is over.

Flash control statuses

Independently from the flash semaphore, the flash driver provides flags – Flash Control Status – to prevent flash operation depending on the system activity. These flags/statuses are checked before any flash operation by the flash driver.

3. Interface

Here comes a list of the available functions for the different Flash management modules:

3.1. Flash Driver

3.1.1. Flash driver error codes

FD_FlashOp_Status_t

Error code	Description
FD_FLASHOP_SUCCESS	No error code
FD_FLASHOP_FAILURE	Error that occurred before any check

3.1.2. Flash driver functions

FD_SetStatus
Description Update Flash Control status. Syntax void FD_SetStatus(FD_Flash_ctrl_bm_t Flags_bm, FD_FLASH_Status_t Status); Parameters [in] Flags_bm Type: FD_Flash_ctrl_bm_t Description: Bit mask identifying the caller [in] Status Type: FD_FLASH_Status_t Description: Action requested (enable or disable flash access) Return Value None

FD_WriteData
Description Write a block of 128 bits (4 32-bit words) in Flash Syntax FD_FlashOp_Status_t FD_WriteData(uint32_t Dest, uint32_t Payload); Parameters [in] Dest Type: uint32_t Description: Address where to write in Flash (128-bit aligned) [in] Payload Type: uint32_t Description: Address of data to be written in Flash (32-bit aligned) Return Value FD_FlashOp_Status_t

FD_EraseSectors
Description Erase one sector of Flash Syntax FD_FlashOp_Status_t FD_EraseSectors(uint32_t Sect); Parameters [in] Sect Type: uint32_t Description: Identifier of the sector to erase Return Value FD_FlashOp_Status_t

3.2. RF Timing Synchro

AMM_Init
Description Initialize the Advanced Memory Manager Pool. Syntax AMM_Function_Error_t AMM_Init (const AMM_InitParameters_t * const p_InitParams); Parameters [in] p_InitParams Type: const AMM_InitParameters_t * const Description: Struct of init parameters Return Value AMM_Function_Error_t

3.3. Flash Manager

AMM_Init
Description Initialize the Advanced Memory Manager Pool. Syntax AMM_Function_Error_t AMM_Init (const AMM_InitParameters_t * const p_InitParams); Parameters [in] p_InitParams Type: const AMM_InitParameters_t * const Description: Struct of init parameters Return Value AMM_Function_Error_t

3.4. Simple NVM Arbiter

AMM_Init
Description Initialize the Advanced Memory Manager Pool. Syntax AMM_Function_Error_t AMM_Init (const AMM_InitParameters_t * const p_InitParams); Parameters [in] p_InitParams Type: const AMM_InitParameters_t * const Description: Struct of init parameters Return Value AMM_Function_Error_t

4. How to

TBD.

5. Revisions

Rev. number	Description
0.1	First wiki version.