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Encoders. Lecture L6.11 Section 6.4. Encoders. Encoders Priority Encoders TTL Encoders. I0. 4-to-2 . I1. A . Encoder . I2. B . I3. Encoders. I0 I1 I2 I3 B A. 1 0 0 0 0 0 0 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 1. I0. I1. A = I1 # I3. I2.
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Encoders Lecture L6.11 Section 6.4
Encoders • Encoders • Priority Encoders • TTL Encoders
I0 4-to-2 I1 A Encoder I2 B I3 Encoders I0 I1 I2 I3 B A 1 0 0 0 0 0 0 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 1
I0 I1 A = I1 # I3 I2 B = I2 # I3 I3 Encoders Assume only 1 input can be high at any time. I0 I1 I2 I3 B A 1 0 0 0 0 0 0 1 0 0 0 1 0 0 1 0 1 0 0 0 0 1 1 1 A = I1 # I3 B = I2 # I3
I0 I1 I2 I3 I4 I5 I6 I7 Y2 Y1 Y0 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 1 1 0 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 1 0 0 1 0 1 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0 1 1 1 1 8-to-3 Encoder Y2 = I7 # I6 # I5 # I4 Y1 = I7 # I6 # I3 # I2 Y0 = I7 # I5 # I3 # I1
encoder.abl MODULE encoder83 TITLE 'Encoder, D. Hanna, 7/15/02' DECLARATIONS " INPUT PINS " I7..I0 PIN 11, 7, 6, 5, 4, 3, 2, 1; " Switch 1..8 " OUTPUT PINS " Y2..Y0 PIN 41, 43, 44 ISTYPE 'com'; " LED 14..16 EQUATIONS Y2 = I7 # I6 # I5 # I4; Y1 = I7 # I6 # I3 # I2; Y0 = I7 # I5 # I3 # I1; END encoder83
Priority Encoder I0 I1 I2 I3 I4 I5 I6 I7 Y2 Y1 Y0 1 0 0 0 0 0 0 0 0 0 0 X 1 0 0 0 0 0 0 0 0 1 X X 1 0 0 0 0 0 0 1 0 X X X 1 0 0 0 0 0 1 1 X X X X 1 0 0 0 1 0 0 X X X X X 1 0 0 1 0 1 X X X X X X 1 0 1 1 0 X X X X X X X 1 1 1 1
Priority Encoder I0 I1 I2 I3 I4 I5 I6 I7 Y2 Y1 Y0 1 0 0 0 0 0 0 0 0 0 0 X 1 0 0 0 0 0 0 0 0 1 X X 1 0 0 0 0 0 0 1 0 X X X 1 0 0 0 0 0 1 1 X X X X 1 0 0 0 1 0 0 X X X X X 1 0 0 1 0 1 X X X X X X 1 0 1 1 0 X X X X X X X 1 1 1 1 Y2 = L7 # L6 # L5 # L4 L7 = I7 L6 = !I7 & I6 L5 = !I7 & !I6 & I5 L4 = !I7 & !I6 & !I5 & I4
Priority Encoder I0 I1 I2 I3 I4 I5 I6 I7 Y2 Y1 Y0 1 0 0 0 0 0 0 0 0 0 0 X 1 0 0 0 0 0 0 0 0 1 X X 1 0 0 0 0 0 0 1 0 X X X 1 0 0 0 0 0 1 1 X X X X 1 0 0 0 1 0 0 X X X X X 1 0 0 1 0 1 X X X X X X 1 0 1 1 0 X X X X X X X 1 1 1 1 Y1 = L7 # L6 # L3 # L2 L7 = I7 L6 = !I7 & I6 L3 = !I7 & !I6 & !I5 & !I4 & I3 L2 = !I7 & !I6 & !I5 & !I4 & !I3 & I2
Priority Encoder I0 I1 I2 I3 I4 I5 I6 I7 Y2 Y1 Y0 1 0 0 0 0 0 0 0 0 0 0 X 1 0 0 0 0 0 0 0 0 1 X X 1 0 0 0 0 0 0 1 0 X X X 1 0 0 0 0 0 1 1 X X X X 1 0 0 0 1 0 0 X X X X X 1 0 0 1 0 1 X X X X X X 1 0 1 1 0 X X X X X X X 1 1 1 1 Y0 = L7 # L5 # L3 # L1 L7 = I7 L5 = !I7 & !I6 & I5 L3 = !I7 & !I6 & !I5 & !I4 & I3 L1 = !I7 & !I6 & !I5 & !I4 & !I3 & !I2 & I1
pencoder.abl MODULE pencoder83 TITLE 'Priority Encoder' DECLARATIONS " INPUT PINS " I0..I7 PIN 11, 7, 6, 5, 4, 3, 2, 1; " Switch 1..8 " OUTPUT PINS " Y2..Y0 PIN 41, 43, 44 ISTYPE 'com'; " LED 14..16 VALID PIN 35; " LED 9 " VALID = 1 for valid binary output
pencoder.abl (cont’d) " Definitions " L7 = I7; L6 = !I7 & I6; L5 = !I7 & !I6 & I5; L4 = !I7 & !I6 & !I5 & I4; L3 = !I7 & !I6 & !I5 & !I4 & I3; L2 = !I7 & !I6 & !I5 & !I4 & !I3 & I2; L1 = !I7 & !I6 & !I5 & !I4 & !I3 & !I2 & I1; EQUATIONS Y2 = L7 # L6 # L5 # L4; Y1 = L7 # L6 # L3 # L2; Y0 = L7 # L5 # L3 # L1; END pencoder83
1 16 Vcc 4 2 15 5 E0 3 14 6 GS 4 13 7 3 5 12 E1 2 6 11 A2 1 7 10 A1 0 8 9 A0 GND 74LS148 TTL Encoder EI 0 1 2 3 4 5 6 7 A2 A1 A0 GS EO 1 X X X X X X X X 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 0 0 X X X X X X X 0 0 0 0 0 1 0 X X X X X X 0 1 0 0 1 0 1 0 X X X X X 0 1 1 0 1 0 0 1 0 X X X X 0 1 1 1 0 1 1 0 1 0 X X X 0 1 1 1 1 1 0 0 0 1 0 X X 0 1 1 1 1 1 1 0 1 0 1 0 X 0 1 1 1 1 1 1 1 1 0 0 1 0 0 1 1 1 1 1 1 1 1 1 1 0 1 Priority Encoder
68000 Interrupt Logic A0 A1 A2 74138 Decoder 68000 IRQA IP0 IP1 IP2 74148 Encoder Peripheral IRQ Data Bus