Mode selection in a flash memory device
View Patent ↗A single flash memory device has selectable read modes for either a segment mode or a page mode. The desired mode is selected by writing a control word to a mode control register. Selecting the segment mode causes the device to output selected memory segments. Selecting the page mode causes the device to output selected memory pages.
1. A flash memory device comprising:
a flash memory array comprising a plurality of flash memory cells;
a control connection for receiving a mode control word; and
control circuitry, coupled to the control connection, for selecting either a page read mode or a segment read mode in response to the received mode control word, wherein the segment read mode outputs selected portions of a page.
2. The flash memory device of claim 1 and further comprising a mode control register for storing the mode control word.
3. The flash memory device of claim 1 and further including a plurality of sense amplifiers coupled to the flash memory array.
4. The flash memory device of claim 3 wherein, in the segment read mode, the flash memory array and the plurality of sense amplifiers are grouped into a plurality of segments such that any one of the flash memory segments can be associated with any one of the plurality of sense amplifier segments.
5. The flash memory device of claim 1 wherein the flash memory array is comprised of a plurality of banks of memory.
6. The flash memory device of claim 4 and further including a plurality of extended address inputs that select from among the plurality of flash memory segments in response to address signal inputs.
7. The flash memory device of claim 1 and further including a state machine that controls memory functions of the flash memory device.
8. The flash memory device of claim 1 and further comprising a plurality of latch circuits grouped into a plurality of segments.
9. A flash memory device comprising:
a flash memory array comprising a plurality of flash memory cells;
page mode synchronous flash memory functional circuitry;
segment mode synchronous flash memory functional circuitry;
control connections for receiving a control word; and
control circuitry, coupled to the control connections, for selecting between the page mode synchronous flash memory functional circuitry and the segment mode synchronous flash memory functional circuitry in response to the received control word.
10. The flash memory device of claim 9 and further including:
a plurality of sense amplifiers coupled to the flash memory array, the plurality of sense amplifiers capable of being grouped into a plurality of segments in response to the control word selecting the segment mode synchronous flash memory functional circuitry, each segment corresponding to a segment of the flash memory; and
a plurality of latches, each latch coupled to a different sense amplifier.
11. The flash memory device of claim 9 wherein the control circuitry is a state machine.
12. The flash memory device of claim 9 and further including a reprogrammable mode control register, coupled to the control circuitry, for storing the received control word.
13. The flash memory device of claim 9 and further including a mode control register coupled to the control circuitry for storing the received control word, the mode control register comprised of non-volatile memory cells that are programmable only once.
14. A flash memory device comprising:
a flash memory array comprising a plurality of flash memory cells;
control connections for receiving a control word; and
a control circuit coupled to the control connections and having a selectable synchronous flash memory function and a virtual synchronous flash memory function, the functions selectable in response to the received control word.
15. The flash memory device of claim 14 wherein the control circuit comprises a state machine that executes the selected synchronous flash memory function or the virtual synchronous flash memory function in response to the received control word.
16. A method for selecting one of a page read mode or a segment read mode in a flash memory device, the method comprising:
receiving a control word over control connections; and
executing either the page read mode or the segment read mode in response to the received control word, wherein the segment read mode outputs selected portions of a page.
17. The method of claim 16 and further comprising reprogramming the control word.
18. An electronic system comprising:
a processor for generating a mode control word and address signals; and
a flash memory device comprising:
a flash memory array comprising a plurality of flash memory cells;
control connections, coupled to the processor, for receiving the mode control word; and
control circuitry that selects either a page read mode or a segment read mode in response to the mode control word, wherein the segment read mode outputs selected portions of a page.
19. The electronic system of claim 18 wherein the address signals are used to select segments of the flash memory array if the segment read mode is selected.
20. The electronic system of claim 19 wherein the flash memory device further includes a mode control register, coupled to the control circuitry, for storing the mode control word.