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Making Measurements
Using Test Sequencing
Electrical specifications for TTL high:
• volts(H) ≥ 2.7 volts (V)
• current = 20 microamps (µA)
Electrical specifications for TTL low:
• volts(L) ≤ 0.4 volts (V)
• current = 0.2 milliamps (mA)
Figure 1-78 Parallel Port Input and Output Bus Pin Locations in GPIO Mode