﻿ Digital Circuits and Systems - Circuits i Sistemes Digitals (CSD) - EETAC - UPC
 Bachelor's Degree in Telecommunications Systems and in Network Engineering
 Lecture 1 L7.1: Counters [P7]  Standard sequential blocks: Synchronous canonical counters [22/4]

2.7. Standard synchronous sequential systems conceived and planned as FSM

2.7.1. Concept map (pdf)(Visio)

2.7.2. Counters

2.7.2.1. Symbol, function table, modulo, timing diagram, state diagram, commercial chips

2.7.2.2. Control signals: count enable (CE), up and down (UD_L) or reversibility

2.7.2.3. Control signals: terminal count (TC) pulse

2.7.2.4. Output code:

2.7.2.4.1. Radix-2 (binary sequential)

2.7.2.4.2. BCD

2.7.2.4.3. One-hot or one-cold

2.7.2.4.4. Gray, Johnson, etc.

2.7.2.5. Design plan X: designing counters as FSM for small number of states and any output code (single-file plan C1 project) as an enumerated FSM like other examples in P6.

2.7.2.5.1. Example. Run the tutorial: Counter_BCD_1digit

A. Counter_mod12 not controlled (CLK, CD)

B. Counter_mod12 with counte enable (CE) and terminal count (TC12)

C. Counter_mod12 reversible (UD_L)

2.7.3. Radix-2 binary counters (Counter_modM), large number of states

2.7.3.1. Symbol, function table, modulo, timing diagram, state diagram, commercial chips

2.7.3.2. Additional control signal: parallel load (LD) or pre-setting output value

2.7.3.3. Design plan Y: designing counters using the VHDL arithmetic library and STD_LOGIC_VECTOR, single-file VHDL project

2.7.3.3.2. Example. Run the tutorial: Counter_BCD_1digit

2.7.3.3.3. Example: versatile/universal Counter_mod16

Comparison of alternative plans for designing counters. Counter_mod12 with parellel load (LD, Din)

Exercise: Draw an example timing diagram (pdf) of the binary counter represented by its symbol and its function table.