Each SLICE of Spartan-6 has 8 storage elements for storage. Four of the memory cells connected to O6 can be configured as registers or latches, while the memory cells connected to O5 can only be configured as registers, as shown in Figure 2-4. This is different from the Spartan-3 family of devices. The multiplexers F7AMUX, F7BMUX, and F8MUX typically implement a variety of multiplexers along with function generators or on-chip logic. In Spartan-6, the LUT can implement the following multiplexers. A LUT implements a 4:1 multiplexer. Two LUTs implement an 8:1 multiplexer. Four LUTs implement a 16:1 multiplexer. MUX has two primitives, MUXF7 and MUXF8. In addition to function generators, SLICEM and SLICEL (not SLICEX) contain a special carry chain for fast arithmetic addition and subtraction in SLICE. There is a carry chain in CLB, which can solve the problem of multi-bit wide addition and multiplication from the lowest bit to the highest bit. The first carry bit logic has a dedicated carry path and a carry multiplexer (MUXCY) that can be used to cascade function generators (LUTs) to implement wider and more complex logic functions and improve the arithmetic operation speed of the CLB. The carry chain in Spartan-6 is the upper travel bit chain, and each SLICE has a height of 4 bits. Taking into account the upstream structure of the carry chain, in the design, pay special attention to the length of the carry chain, because if the carry chain length exceeds a column, the carry will cause the delay to become much longer, affecting the timing. The fast first move bit logic has a primitive, CARRY4. The arithmetic logic consists of an exclusive OR gate (XOR) and a dedicated AND gate (MULT_AND). An XOR gate allows a SLICE to implement a 2-bit full-add operation, and a dedicated AND gate increases the efficiency of the multiplier. Handheld Megaphone,Portable Megaphone,Hand Held Loud Speaker,Portable Megaphone With Microphone Shangqiu Huayitong electronic technology co., Ltd. , https://www.huayitongmegaphones.com