System and method for controlling flash memory without using ready/busy signal
A system and method for controlling flash memory is provided for a flash memory controller to use a control interface to read the state register of at least a flash memory with received data for operation to detect whether the flash memory has already finished the operation on the received data without using an RB signal, and when the operation on the received data is to read, the controller can execute the state data switch so that the IO of flash memory can output correct flash memory data for read, or when the operation on the received data is to write, the controller can execute another data operation to save time and accelerate the data operation speed of the flash memory.
1. A method for controlling flash memory, using a flash memory controller to perform a data read operation on a flash memory to read data, and a control interface existing between said flash memory and said flash memory controller, said control interface comprising: a ready/busy (RB) signal, a chip enable (CE) signal, an address latch enable (ALE) signal, a command latch enable (CLE) signal, a read enable (REN) signal, a write enable (WEN) signal, a write protect (WPN) and an input/output (IO) bus, wherein said method realizes said data read operation without using said RB signal, and comprises the steps of:
(a) using said control interface to transmit a read command to said flash memory;
(b) reading a state register of said flash memory, said state register comprising a state bit, said state bit indicating whether said flash memory has finished said read command or not;
(c) determining level of said state bit, if said state bit is at a first level, returning to step (b), and if said state bit is at a second level, proceeding to step (d);
(d) performing a state data switch on said flash memory;
(e) repeatedly lowering said REN signal to low level and raising said REN signal to high level to capture memory data on said IO; and
(f) accomplishing said data read operation;
wherein said state data switch in step (d) comprises serially inputting a plurality of commands including a random data out command.
2. The method as claimed in claim 1 , wherein said data read operation is one of page read operation, page read cache mode operation, random data out operation and two-plane page read operation.
3. The method as claimed in claim 1 , wherein said first level is high level, and said second level is low level.
4. The method as claimed in claim 1 , wherein said first level is low level, and said second level is high level.
5. The method as claimed in claim 1 , wherein said random data out command comprises inputting a first command code, a memory address and a second command code to said IO.
6. The method as claimed in claim 1 , wherein state data switch further comprises a starting command before said random data out command, said starting command comprises command code 00h, and has at least a time length of system cycle.
7. A method for controlling flash memory, using a flash memory controller to perform a data write operation on a flash memory to write data into said flash memory, and a control interface existing between said flash memory and said flash memory controller, said control interface comprising: a ready/busy (RB) signal, a chip enable (CE) signal, an address latch enable (ALE) signal, a command latch enable (CLE) signal, a read enable (REN) signal, a write enable (WEN) signal, a write protect (WPN) and an input/output (IO) bus, wherein said method realizes said data write operation without using said RB signal, and comprises the steps of:
(a) using said control interface to transmit a write command to said flash memory;
(b) reading a state register of said flash memory, said state register comprising a state bit, said state bit indicating whether said flash memory has finished said write command or not;
(c) determining level of said state bit, if said state bit is at a first level, returning to step (b), and if said state bit is at a second level, proceeding to step (d); and
(d) accomplishing said data write operation.
8. The method as claimed in claim 7 , wherein said data write operation is one of page write operation, page write cache mode operation, random data in operation and two-plane page write operation.
9. The method as claimed in claim 7 , wherein said first level is high level, and said second level is low level.
10. The method as claimed in claim 7 , wherein said first level is low level, and said second level is high level.