The CY29FCT520T is a multilevel 8-bit-wide pipeline register. The device consists of four registers, A1, A2, B1, and B2, which are configured by the instruction inputs I0, I1 as a single four-level pipeline or as two two-level pipelines. The contents of any register can be read at the multiplexed output at any time by using the multiplex-selection controls (S0 and S1). The pipeline registers are positive-edge triggered, and data is shifted by the rising edge of the clock input. Instruction I = 0 selects the four-level pipeline mode. Instruction I = 1 selects the two-level B pipeline, while I = 2 selects the two-level A pipeline. I = 3 is the hold instruction; no shifting is performed by the clock in this mode. In the two-level operation mode, data is shifted from level 1 to level 2 and new data is loaded into level 1. This device is fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.