Device Geometry - 2023.1 English

Intel Flash Device Geometry

Flash memory space is segmented into areas called blocks. The size of each block is based on a power of 2. A region is defined as a contiguous set of blocks of the same size. Some parts have several regions while others have one. The arrangement of blocks and regions is referred to by this module as the part's geometry. Some Intel flash supports multiple banks on the same device. This library supports single and multiple bank flash devices.

AMD Flash Device Geometry

Flash memory space is segmented into areas called banks and further in to regions and blocks. The size of each block is based on a power of 2. A region is defined as a contiguous set of blocks of the same size. Some parts have several regions while others have one. A bank is defined as a contiguous set of blocks. The bank may contain blocks of different size. The arrangement of blocks, regions and banks is referred to by this module as the part's geometry. The cells within the part can be programmed from a logic 1 to a logic 0 and not the other way around. To change a cell back to a logic 1, the entire block containing that cell must be erased. When a block is erased all bytes contain the value 0xFF. The number of times a block can be erased is finite. Eventually the block will wear out and will no longer be capable of erasure. As of this writing, the typical flash block can be erased 100,000 or more times.

Write Operation

The write call can be used to write a minimum of zero bytes and a maximum entire flash. If the Offset Address specified to write is out of flash or if the number of bytes specified from the Offset address exceed flash boundaries an error is reported back to the user. The write is blocking in nature in that the control is returned back to user only after the write operation is completed successfully or an error is reported.

Read Operation

The read call can be used to read a minimum of zero bytes and maximum of entire flash. If the Offset Address specified to write is out of flash boundary an error is reported back to the user. The read function reads memory locations beyond Flash boundary. Care should be taken by the user to make sure that the Number of Bytes + Offset address is within the Flash address boundaries. The read is blocking in nature in that the control is returned back to user only after the read operation is completed successfully or an error is reported.

Erase Operation

The erase operations are provided to erase a Block in the Flash memory. The erase call is blocking in nature in that the control is returned back to user only after the erase operation is completed successfully or an error is reported.

Sector Protection

The Flash Device is divided into Blocks. Each Block can be protected individually from unwarranted writing/erasing. The Block locking can be achieved using XFlash_Lock() lock. All the memory locations from the Offset address specified will be locked. The block can be unlocked using XFlash_UnLock() call. All the Blocks which are previously locked will be unlocked. The Lock and Unlock calls are blocking in nature in that the control is returned back to user only after the operation is completed successfully or an error is reported. The AMD flash device requires high voltage on Reset pin to perform lock and unlock operation. User must provide this high voltage (As defined in datasheet) to reset pin before calling lock and unlock API for AMD flash devices. Lock and Unlock features are not tested for AMD flash device.

Device Control