文档介绍：FIFO详解
A thorough understanding of FIFO (including explanations with FIFO depth)
FIFO:
A FIFO queue (First Input Firs12 8 bit data, the depth of the FIFO can be small or large, personally think that the FIFO depth calculation is not a fixed formula. In FIFO actual work, the full / empty sign of the data can control the continued write or read of data. In a specific application could not count by some parameters required for accurate FIFO depth is much, it is feasible in the write speed is greater than the read speed under ideal conditions, but the depth of FIFO used in practice is often greater than the calculated value. In general, it is possible to estimate a given width and depth based on the specific circumstances of the circuit, taking into account both system performance and FIFO cost. For applications that write at a slower rate than the read speed, the depth of the FIFO is determined by the specific requirements of the read data structure and the readout data.
Full flag: a signal sent by the state circuit of the FIFO when the FIFO is full or will be full to prevent the write operation of the FIFO from continuing to write data to the FIFO (overflow).
Null flag: a signal sent by the state circuit of the FIFO when the FIFO is empty or will be empty, to prevent the read operation of the FIFO from reading data from the FIFO, resulting in the readout of invalid data (und