Extended address mode for serial flash memory
View Patent ↗Example embodiments for providing enhanced addressability for a serial flash memory device may comprise providing an extended addressing mode to enable access to a larger range of memory locations.
1. A method of providing extended memory addressing in a compatible manner, the method comprising:
in a serial flash memory device in which both addresses and data are communicated serially, initially entering a default addressing mode corresponding to a standard upon power-up for conformity with the standard, wherein addressing with the default addressing mode permits addressing of only a subset of memory locations of the serial flash memory device, wherein the subset of memory locations is smaller than the total memory locations;
performing read and write memory operations at the serial flash memory device using the default addressing mode when no command for an extended addressing mode is received;
entering the extended addressing mode and performing read and write memory operations at the serial flash memory device using the extended addressing mode comprising an extended number of address bits providing access to a set of memory locations larger than and including the subset of memory locations at least in part in response to receiving an address length configuration command code from a processor; and
serially receiving addresses for the read and write memory operations from the processor.
2. The method of claim 1 , wherein the default addressing mode comprises a twenty-four bit addressing mode.
3. The method of claim 2 , wherein the standard comprises a serial peripheral interface protocol.
4. The method of claim 2 , wherein the extended addressing mode comprises a thirty-two bit addressing mode.
5. The method of claim 4 , wherein the extended addressing mode comprises a thirty-two bit addressing mode compatible with a serial peripheral interface protocol.
6. The method of claim 1 , further comprising transmitting a device identification value to a processor at least in part in response to a device identification read operation initiated by the processor, the device identification value to indicate at least in part that the serial flash memory device is capable of performing extended addressing mode operations.
7. The method of claim 1 , further comprising transmitting common flash memory interface (CFI) information to a processor at least in part in response to a CFI read operation initiated by the processor, the CFI information to indicate at least in part that the serial flash memory device is capable of performing extended addressing mode operations.
8. The method of claim 1 , further comprising transmitting boot-up code to a processor at least in part in response to a read operation initiated by the processor, the boot-up code to indicate at least in part that the serial flash memory device is capable of performing extended addressing mode operations.
9. A serial flash memory device, comprising:
a plurality of memory locations; and
a control unit configured to receive addresses serially, to receive data for writes serially, and to provide data for reads serially, the control unit configured to perform read and write memory operations in a default addressing mode when no command for an extended addressing mode is received, the default addressing mode having a default number of address bits providing access to a subset of memory locations, the control unit further configured to perform read and write memory operations in an extended addressing mode at least in part in response to receiving an address length configuration command code, the extended addressing mode having an extended number of address bits providing access to a set of memory locations larger than and including the subset of memory locations.
10. The serial flash memory device of claim 9 , wherein the default addressing mode comprises a twenty-four bit addressing mode.
11. The serial flash memory device of claim 10 , wherein the default addressing mode comprises a twenty-four bit addressing mode compatible with a serial peripheral interface protocol.
12. The serial flash memory device of claim 10 , wherein the extended addressing mode comprises a thirty-two bit addressing mode.
13. The serial flash memory device of claim 12 , wherein the extended addressing mode comprises a thirty-two bit addressing mode compatible with a serial peripheral interface protocol.
14. The serial flash memory device of claim 9 , further comprising an output terminal to transmit a device identification value to a processor at least in part in response to a device identification read operation initiated by the processor, the device identification value to indicate at least in part that the serial flash memory device is capable of performing extended addressing mode operations.
15. The serial flash memory device of claim 9 , further comprising an output terminal to transmit common flash memory interface (CFI) information to a processor at least in part in response to a CFI read operation initiated by the processor, the CFI information to indicate at least in part that the serial flash memory device is capable of performing extended addressing mode operations.
16. The serial flash memory device of claim 9 , further comprising an output terminal to transmit boot-up code to a processor at least in part in response to a read operation initiated by the processor, the boot-up code to indicate at least in part that the serial flash memory device is capable of performing extended addressing mode operations.
17. A system, comprising:
a processor; and
a serial flash memory device coupled to the processor, the memory device comprising
a plurality of memory locations, and
a control unit configured to receive addresses serially, to receive data for writes serially, and to provide data for reads serially, the control unit configured to perform read and write memory operations in a default addressing mode when no command for an extended addressing mode is received, the default addressing mode having a default number of address bits providing access to a subset of the plurality of memory locations, the control unit further configured to perform read and write memory operations in an extended addressing mode at least in part in response to receiving an address length configuration command code from the processor comprising an extended number of address bits providing access to a set of the plurality of memory locations larger than and including the subset of memory locations.
18. The system of claim 17 , wherein the default addressing mode comprises a twenty-four bit addressing mode compatible with a serial peripheral interface protocol.
19. The system of claim 18 , wherein the extended addressing mode comprises a thirty-two bit addressing mode.
20. The system of claim 17 , the memory device further comprising an output terminal to transmit addressing mode capability information to the processor at least in part in response to a read operation initiated by the processor, the addressing mode capability information to indicate at least in part that the memory device is capable of performing extended addressing mode operations.