ITPEC FE Morning October 2018 Question 24
ITPEC FE Morning October 2018 — Question 24 of 80
7-Segment LED Display (Anode-Common) — determine which digit is shown from a hex output value.
Convert hex to binary and map bits to segments:
- •
0x92=10010010 - •P7 (MSB) → Dt, P6 → g, P5 → f, P4 → e, P3 → d, P2 → c, P1 → b, P0 (LSB) → a
Anode-common rule: LED lights up when output bit = 0 (current sinks through cathode).
Segments ON (bit = 0): a, c, d, f, g → displays 5, dot is OFF.
Why not others:
- (a) — different segment combination
- (b) — different segment combination with dot off
- (d) — different segment combination with dot on
Key rule: In anode-common circuits, 0 = ON and 1 = OFF. Always invert the bit pattern before mapping to segments.
AI-generated — may contain errors
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