1. [10%] A microcontroller is connected through its 16-bit address bus to a peripheral device, which is memory mapped to 4000H - 47FFH. Please show how you design an address decoder for the device using a NAND gate. 2. [5%] To emulate analog signals, what are the differences between using DAC output and PWM pulses from timer? 3. [5%] Why we need sample-and-hold circuitry for data acquisition? Is sample-and-hold circuitry more critical for a high-frequency or low-frequency signal and why? 4. [5%] How to check buffer full In FC communication? 5. [20%] Write the code to process an analog signal with 256 Hz sampling rate. A function, which takes 26 ms to do the DSP computation, is called every 32 samples. Please also draw the timing diagram to show the timing relationship among ISRs and the DSP function. : 5v O MCLR/V PP/RE3 -RACANi RA1/AN1 2/AN2/VREF-/CVREF R Na 111 03 4 AWN