Questions 1&2

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	WHAT'S YOUR ENGINEERING QUOTIENT?
•Step up to the plate. Problem 1—The Motorola 68K processors have conditional branches that operate on the basis of condition codes set by a previous instruction. However, some confusion can occur as both the following instruction sequences will branch if VALUE = 8, although the branch instructions needed are exact opposites. MOVE.B #VALUE, D0 MOVE.B #VALUE, D0 AND.B #0x08, D0 CMPI.B #0x08, D0 BNE SOMEWHERE BEQ SOMEWHERE A possibly third alternative would be to use a `BTST #3, D0` instruction to control the branching. When the `BTST` instruction tests the 3rd bit does it behave more like the `AND` instruction or the `CMPI` instruction? ANSWER Problem 2—The integrate-and-fire model is one of the simplest models of a sensory neuron. It consists of a leaky integrator followed by a threshold trigger. When the trigger fires, it resets the integrator. Clearly, a constant input will result in a constant firing rate, provided the level is high enough. Otherwise the neuron will never fire. What happens to the neuron's sensitivity if the input also contains broadband noise? ANSWER 11-00