01 / 63ECE 511: Digital System & Microprocessor
1 / 17
Télécharger la présentation
ECE 511: Digital System & Microprocessor
Une image / un lien ci-dessous est fourni (tel quel) pour télécharger la présentation
Politique de téléchargement : le contenu du site vous est fourni TEL QUEL pour votre information et votre usage personnel ; il ne peut être vendu, concédé sous licence ni partagé sur d’autres sites sans l’accord de son auteur.Le contenu vous est fourni TEL QUEL, pour votre information et votre usage personnel uniquement.Téléchargez la présentation en cliquant sur ce lien.Lors du téléchargement, si vous ne parvenez pas à télécharger une présentation, l’éditeur a peut-être supprimé le fichier de son serveur.Pendant le téléchargement, si vous ne parvenez pas à obtenir une présentation, le fichier a peut-être été supprimé par l’éditeur.
References • J. L. Antonakos, “The 68000 Microprocessor: Hardware and Software Principles & Applications,” 5th Ed., Pearson Prentice-Hall, 2004. • C. M. Gilmore, “Microprocessors: Principles & Applications,” 2nd Ed., McGraw-Hill, 1995. • A. Clements, “Microprocessor System Design,” PWS-Kent, 1992.
Course Evaluation • Tests x 2 30% • Quizzes x 3 20% • Mini Projects 50%
If you have problems, please contact me: Ahmad Ihsan bin Mohd Yassin Rm. T2-A13-1A, Dept. of Comp. Eng. Faculty of Elect. Eng. UiTM, Shah Alam. 03-55436118, 017-2576295 *Please call before you see me.
What are gates? • Gates are: • Simple electronic devices. • Constructed using transistors. • Used to design digital systems. • Three Basic Gates: • AND • OR • NOT • Basic Gates can be combined into Extended Gates. • Usually packed into ICs.
Flip-Flops • An extended gate used as memory: • Each FF stores 1 bit. • 2 gates, feedback connections. • 2 inputs, 2 outputs. • More complex ones may: • Use timing from CLK. • Perform bit toggle.
Reset-Set (RS) Flip-Flop • 4 states: • Three stable (Set, Reset, and Keep). • One not stable (Unused). • 2 inputs, 2 outputs. • May also contain clock (CLK) signal.
RS Flip-Flop RSFF R Q *Assuming initial condition: S = 0, R = 0, Q = 0 S Q’ Qprev S R Q Q’ KEEP: Output unchanged N/A 0 0 0 1 SET: Output set (Q = 1) 0 1 0 1 0 RESET: Output reset (Q = 0) 1 0 1 0 1 *As long as S=0 and R=0, Q will always remain at previous state. Doesn’t matter 1 1 N/A N/A Unstable
Clocked RS Flip-Flop RSFF R Q *Assuming initial condition: S = 0, R = 0, Q = 0 CLK Qprev S R CLK Q Q’ S Q’ KEEP: Output unchanged N/A 0 0 ↑ 0 1 0 Doesn’t matter Doesn’t matter ↓ 0 1 Only active when CLK is ↑ SET: Output set (Q = 1) 0 1 0 ↑ 1 0 RESET: Output reset (Q = 0) 1 0 1 ↑ 0 1 Reduced sensitivity to noise. Doesn’t matter 1 1 ↑ N/A N/A Unstable
Qprev J K Q Q’ N/A 0 0 0 1 Output unchanged 0 1 0 1 0 Output set (Q = 1) 1 0 1 0 1 Output reset (Q = 0) Q 1 1 Q Q Toggle JK Flip-Flop • Same as RS, but forbidden state used to toggle bit. • Can also be clocked using CLK. *Assuming initial condition: J = 0, K = 0, Q = 0
Qprev S R Q Q’ N/A 0 0 0 1 Output unchanged 0 1 0 1 0 Output set (Q = 1) 1 0 1 0 1 Output reset (Q = 0) Q 1 1 Q Q Toggle JK Flip-Flop J Q K Q *Assuming initial condition: J = 0, K = 0, Q = 0
Clocked JK J Q CLK K Q Qprev S R CLK Q N/A 0 0 ↑ 0 Output unchanged 0 Doesn’t matter Doesn’t matter ↓ 0 Only active when CLK is ↑ 0 1 0 ↑ 1 Output set (Q = 1) 1 0 1 ↑ 0 Reduced sensitivity to noise. Output reset (Q = 0) Q 1 1 ↑ Q Toggle
D-Flip-Flop • Data latch. • Modification of RSFF. • Stores 1-bit of information. • Can be combined to store more. • Data are stored in memory using millions of DFFs.
D-Flip-Flop DFF D Q EN Q’ Qprev D EN Q Q’ QPREV Doesn’t Matter 0 QPREV Q’PREV *Only active when EN is 1 Doesn’t Matter 1 1 1 0 Output set (Q = 1) Doesn’t Matter 0 1 0 1 Output reset (Q = 0)
NAND and NOR as Universal Gates • In industry, NAND and NOR gates are most common. • Reason? • Can be used to represent any gate (functionally complete). • Easiest & cheapest to produce.
Decoder • A digital circuit that detects a specific combination of input bits (code), and indicates the presence of the code by a specific output. • Typically has n inputs and 2n outputs, but other combinations also exist. • However, the number of inputs is always less than the outputs (noInputs < noOutputs). • Each combination of inputs will generate a unique pattern at the output.
2-4 Decoder Y0 I0 Y1 Y2 I1 Y3 Example: Active High 2-4 Decoder I1 I0 Y3 Y2 Y1 Y0 0 0 0 0 0 1 0 1 0 0 1 0 1 0 0 1 0 0 1 1 1 0 0 0 A specific pattern at the inputs. Will activate a specific bit at the outputs.
2-4 Decoder Y’0 I0 Y’1 Y’2 I1 Y’3 Example: Active Low 2-4 Decoder I1 I0 Y’3 Y’2 Y’1 Y’0 0 0 1 1 1 0 0 1 1 1 0 1 1 0 1 0 1 1 1 1 0 1 1 1 A specific pattern at the inputs. Will activate a specific bit at the outputs.
Decoders • In this subject, you need to familiarize yourself with two types of decoders: • 74LS139 Dual 2-4 Line Decoder. • 74LS138 3-8 Line Decoder • Decoders are used to: • Activate devices for use by µP. • Memory, I/O interfacing.
74LS139 Dual 2-4 Line Decoder • Motorola active low 2-4 decoder. • 2 x decoders in one IC. • 16 pins total: • 2 x (2 inputs, 4 outputs). • Vcc (±5V) and GND. • 2 x Enable pins.
Connexion au compte
Connectez-vous pour publier votre contenu sur SlideServe.