Does my flash need updating
Does my flash need updating - azdg dating ge
While EPROMs had to be completely erased before being rewritten, NAND-type flash memory may be written and read in blocks (or pages) which are generally much smaller than the entire device.
The low read latencies characteristic of NOR devices allow for both direct code execution and data storage in a single memory product.
In NOR flash, each cell has one end connected directly to ground, and the other end connected directly to a bit line.
This arrangement is called "NOR flash" because it acts like a NOR gate: when one of the word lines (connected to the cell's CG) is brought high, the corresponding storage transistor acts to pull the output bit line low.
Despite the need for high programming and erasing voltages, virtually all flash chips today require only a single supply voltage, and produce the high voltages using on-chip charge pumps.
Over half the energy used by a 1.8 V NAND flash chip is lost in the charge pump itself.
Multi-level cell (MLC) devices, including triple-level cell (TLC) devices, can store more than one bit per cell.
The floating gate may be conductive (typically polysilicon in most kinds of flash memory) or non-conductive (as in SONOS flash memory).The presence of a logical "0" or "1" is sensed by determining whether there is current flowing through the transistor when the intermediate voltage is asserted on the CG.In a multi-level cell device, which stores more than one bit per cell, the amount of current flow is sensed (rather than simply its presence or absence), in order to determine more precisely the level of charge on the FG.This makes NAND flash unsuitable as a drop-in replacement for program ROM, since most microprocessors and microcontrollers require byte-level random access.In this regard, NAND flash is similar to other secondary data storage devices, such as hard disks and optical media, and is thus highly suitable for use in mass-storage devices, such as memory cards.Once the FG is charged, the electrons in it screen (partially cancel) the electric field from the CG, thus, increasing the threshold voltage (V), and hence, a logical "1" is stored in the gate.