First-in first-out memory device and electronic apparatus having the same

摘要

A first-in first-out (FIFO) memory device includes a main FIFO unit, an auxiliary FIFO unit and a control unit. The main FIFO unit includes first through N-th one-port memories, each of which including M entries, where N and M are integers greater than or equal to two. The auxiliary FIFO unit includes one dual-port memory having M entries. The control unit performs a write operation by receiving a write command and data and storing the data in one of the main FIFO unit and the auxiliary FIFO unit based on an operating mode, and performs a read operation by receiving a read command and reading the data from one of the main FIFO unit and the auxiliary FIFO unit based on the operating mode.

主权项

1. A first-in first-out (FIFO) memory device, comprising:
a main FIFO unit including first through N-th one-port memories, each of the first through the N-th one-port memories including M entries, wherein N and M are integers greater than or equal to two; an auxiliary FIFO unit including one dual-port memory, the dual-port memory including M entries; and a control unit configured to perform a write operation by receiving a write command and data and storing the data in one of the main FIFO unit and the auxiliary FIFO unit based on an operating mode, and configured to perform a read operation by receiving a read command and reading the data from one of the main FIFO unit and the auxiliary FIFO unit based on the operating mode, wherein the operating mode is based on whether a pointer corresponding to the write operation references a same one of the one-port memories as a pointer corresponding to the read operation, wherein the control unit includes a virtual write pointer and a virtual read pointer, which circularly indicate entries of the first through the N-th one-port memories from a first entry of the first one-port memory to a last entry of the N-th one-port memory, and an auxiliary write pointer and an auxiliary read pointer, which circularly indicate entries of the dual-port memory from a first entry of the dual-port memory to a last entry of the dual-port memory, increments both the virtual write pointer and the auxiliary write pointer after performing the write operation and increments both the virtual read pointer and the auxiliary read pointer after performing the read operation, wherein the control unit determines the operating mode as a normal mode if an entry indicated by the virtual write pointer and an entry indicated by the virtual read pointer are included in different one-port memories, wherein the control unit determines the operating mode as a first conflict mode if an entry indicated by the virtual write pointer and an entry indicated by the virtual read pointer are included in a same one-port memory, and the virtual read pointer precedes the virtual write pointer or the virtual write pointer and the virtual read pointer indicate a same entry, wherein the control unit determines the operating mode as a second conflict mode if an entry indicated by the virtual write pointer and an entry indicated by the virtual read pointer are included in a same one-port memory, and the virtual write pointer precedes the virtual read pointer or the virtual write pointer and the virtual read pointer indicate a same entry, and wherein the control unit further includes a mode switch pointer and a read flag, and the control unit sets up the mode switch pointer to indicate an entry indicated by the virtual write pointer when the operating mode is switched from the normal mode to the first conflict mode, sets the read flag to a first value when the control unit reads the data from the main FIFO unit in response to the read command, and sets the read flag to a second value when the control unit reads the data from the auxiliary FIFO unit in response to the read command.