Method and apparatus for reading data stored in flash memory by referring to binary digit distribution characteristics of bit sequences read from flash memory

A method for reading data stored in a flash memory, comprising:

• reading a plurality of memory cells of the flash memory by using a plurality of control gate voltages to obtain a plurality of bit sequences from the flash memory;
• referring to the plurality of bit sequences to determine numbers of memory cells whose threshold voltages are located between a first control gate voltage and a second control gate voltage of the plurality of control gate voltages, to generate a first value;
• referring to the plurality of bit sequences to determine numbers of memory cells whose threshold voltages are located between a third control gate voltage and a fourth control gate voltage of the plurality of control gate voltages, to generate a second value;
• and
• updating at least one of the plurality of control gate voltages according to the first value and the second value.

An electronic device, comprising:

• a flash memory;
• and
• a flash memory controller, configured to perform the steps of:
• reading a plurality of memory cells of the flash memory by using a plurality of control gate voltages to obtain a plurality of bit sequences from the flash memory;
• referring to the plurality of bit sequences to determine numbers of memory cells whose threshold voltages are located between a first control gate voltage and a second control gate voltage of the plurality of control gate voltages, to generate a first value;
• referring to the plurality of bit sequences to determine numbers of memory cells whose threshold voltages are located between a third control gate voltage and a fourth control gate voltage of the plurality of control gate voltages, to generate a second value;
• and
• updating at least one of the plurality of control gate voltages according to the first value and the second value.