13189402

Paragraph Number

285

In certain embodiments, the solid-state storage media 110 may employ a two-phase programming model. In such a model, a binary value is first written to the LSB by way of a first write command to the lower page. The write command causes the multi-level storage cell to move from its initial state (for example, a 11 state in L0) to an intermediate state (the lower-to-middle LM state—between L1 and L2) configured such that a 00 state is subsequently read. For example, writing a “0” to the lower page causes the multi-level storage cell to change from the L0 state (where both the LSB and the MSB are 1) to the L2 state (where the LSB is changed to a 0). A subsequent write of a “0” to the upper page moves the multi-level storage cell from the intermediate state (typically between the L1 state and the L2 state) to L2 state such that both bits of the MLC are “0”. Thus, in such an embodiment, two writes (one to the lower page and one to the upper page) are needed to move the multi-level cell from L0 to L2, since the cell transitions through the intermediate state and the MLC device requires that the lower page be programmed before the upper page and does not allow partial programming of a page without an intervening erase operation. Writing a “1” to either of the upper page or lower page will cause the MLC to transition to either L1 or L3 depending on the binary value of the lower page at the time. In addition, certain solid-state media vendors may impose a requirement that the lower page must be written to before the upper page, or the like. In other embodiments, the solid-state storage media 110 may employ a two-phase programming model where a binary value is first written to the MSB by way of a first write command to the upper page.

Added by DJM 3 2021