1. Describe the actions of the following pins. Answer first how they react to getting 1 as an input and then answer how they react to getting 0 as an input

i) TEST ii) EOP (2 marks)

2. Please briefly explain how 3 8237 DMA controllers connected to another 8237 DMA controller can be used in a cascade manner with figures. (3 marks)

MOD = 11 EFFECTIVE ADDRESS CALCULATION R/M W=0 W=1 R/M MOD=00 MOD=01 MOD = 10 000 001 010 011 100 101 110 111 AL CL DL BL AH CH DH BH AX CX DX BX SP BP SI DI 000 001 010 011 100 101 110 111 (BX) + (SI) (BX) + (DI) (BP) + (SI) (BP) +(DI) (SI) (DI) DIRECT ADDRESS (BX) (BX) + (SI) + DB (BX) + (DI) + D8 (BP) + (SI) + D8 (BP)+(DI) + D8 (SI) +D8 (DI) + D8 (BP)+D8 (BX) + D8 (BX)+(SI) + D16 (BX) + (DI) + D16 (BP) + (SI) +D16 (BP)+(DI) + D16 (SI) + D16 (DI) +D16 (BP)+D16 (BX) +D16 Figure: R/M vs MOD Chart for MOV: 100010 instruction REGISTER SELECT (SEE FIGURE 3-7) BYTE 3 BYTE 4 BYTE 1 10101010 OP CODE DW MOD LOW DISPLACEMENT HIGH DISPLACEMENT REG RM OR DIRECT ADDRESS LOW BYTE DIREST ADDRESS HIGH BYTE (5 BITS) ADDRESSING MODE (SEE FIGURE 3.8) BYTENORD DATA OBYTE 1 = WORD DIRECTION TO FROM REG 0 = FROM 1 - TO OPERATION CODE