DESCRIPTION
Some applications the LF9502 is useful for include sample rate conversion, data time compression/expansion, software controlled data alignment, and programmable serial data shifting. The data recirculation mode provides a feedback path from the data output to the data input for use as a programmable circular buffer. By using the length control input (LC10-0) and the length control enable (LCEN) the length of the delay buffer or amount of recirculation delay can be programmed. Providing a delay value on the LC10-0 inputs and driving LCEN LOW will load the delay value into the length control register on the next selected clock edge. Two registers, one preceeding the programmable delay RAM and one following, are included in the delay path. Therefore, the programmed delay value should equal the desired delay minus 2. This consequently means that the value loaded into the length control register must range from 0 to 2047 (to provide an overall range of 2 to 2049). The active edge of the clock input, either positive or negative edge, can be selected with the clock select (CLKSEL) input.
LOGIC Devices Incorporated
