11&12

一、Applications of Flip-Flops 1，Example 1 - Data Latching

2，register A register is a group of flip-flops connected together and operated as a unit. Each bit of the register is implemented as a flip-flop cell

Flip-Flop Transfers for Bit-Wise Shifting触发传输按位移动

In magnitude terms, a shift operation can be to the left (LSB to MSB) or to the right (MSB to LSB). 左×右÷ Shifting to the right is the same as dividing the binary value by 2. Shifting to the left is the same as multiplying by 2.

3，Shift Registers a right shift operation takes place on a 4-bit register. Note that the value 0 has been used to replace the Most-Significant-Bit (MSB) and the least significant bit value has been lost from the register. | 0 | 1 | 1 | 0 | |-------|-----|-----|-----| | 0 | 0 | 1 | 1 |

二 Exp3，- Asynchronous Counter Note that the frequency of Q1 is half that of Q0 . 1,Asynchronous Counter – Cumulative Propagation Delay

2,

If each flip-flop represented a 50ns propagation delay, this asynchronous counter circuit would have a 200ns propagation delay. The time delay between clock pulses must be longer than this for correct operating sequence. This makes the circuit slower

3,In the example above, consider the counter changing from 1111 to 0000 after a clock pulse occurs.

三、Synchronous Sequential Circuits When all clocked flip-flops in a digital system have their clock lines connected to the same clock source, the circuit is said to be a synchronous circuit.

Example 4 - Synchronous Counter

1，