QUESTIONS AND PROBLEMS 10.1 What are the basic differences between the 68000,68008,68010, and 68012? 10.2 What D0es a HIGH on the 68000 FC2 pin indicate? 10.3 (a) If a 68000-based system operates in the user mode and an interrupt occurs, what will the 68000 mode be? (b) If a 68000-based system operates in the supervisor […]
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MOTOROLA MC68000
68000 exception handlin , 68000/2732/6116/6821-based microcomputer , multiprocessine with the 68000 using the tas instruction and the as sienal .
10.13 68000 Exception Handlin : A 16-bit microcomputer is usually capable of hanD1ing unusual or exceptional conditions. These conditions include situations such as execution of illegal instruction or division by zero. In this section, the exception-hanD1ing capabilities of the 68000 are described. The 68000 exceptions can be divided into three groups, namely, groups 0, 1, […]
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68000 memory interface , 68000 i/o , 68000 programmed i/o , 68000/6821 interface , 68000/68230 interface , 68000 interrupt system , external interrupts , internal interrupts , 68000 interrupt map , 68000 interrupt address vector , an example of autovector and nonautovector interrupts , interfacing a typical aid converter to the 68000 using autovector and nonautovector interrupts and 68000 dma .
10.10 68000 Memory Interface One of the advantages of the 68000 is that it can easily be interfaced to memory chips with various speeds because it goes into a wait state if DTACK is not asserted (LOW) by the memory devices at the end of S4. A simplified schematic showing an interface of a 68000 […]
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68000 clock and reset signals , 68000 clock signals , 68000 reset circuit and 68000 read and write cycle timing diagrams .
10.9 68000 Clock and Reset Signals This section covers generation of 68000 clock and reset signals in detail because the clock signal and the reset pins are two important signals of any microprocessor. 10.9.1 68000 Clock Signals As mentioned before, the 68000 D0es not include an on-chip clock generation circuitry. This means that an external […]
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68000 pins and signals , synchronous and asynchronous control lines , interrupt control lines , dma control lines and status lines
10.8 68000 Pins And Signals The 68000 is usually packaged in one of the following: a) 64-pin dual in-line package (DIP) b) 68-pin quad pack c) 68-terrninal chip carrier d) 68-pin grid array (PGA) Figure 10.6 shows the 68000 pin diagram for the DIP. Appendix C provides data sheets for the 68000 and support chips. […]
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68000 pins and signals , synchronous and asynchronous control lines , system control lines , interrupt control lines , dma control lines and status lines
10.8 68000 Pins And Signals The 68000 is usually packaged in one of the following: a) 64-pin dual in-line package (DIP) c) 68-terrninal chip carrier b) 68-pin quad pack d) 68-pin grid array (PGA) Figure 10.6 shows the 68000 pin diagram for the DIP. Appendix C provides data sheets for the 68000 and support chips. […]
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Program control instructions , system control instructions and 68000 stack
10.6.1 Program Control Instructions These instructions include branches, jumps, and subroutine calls as listed in Table 10.11. Consider Bee d. There are 14 branch conditions. This means that the cc in Bee can be replaced by 14 conditions providing 14 instructions: BCC, BCS, BEQ, BGE, BGT, BHI, BLE, BLS, BLT, BMI, BNE, BPL, BVC, and […]
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Logical instructions , shift and rotate instructions , bit manipulation instructions and binary-coded-decimal instructions
10.6.1 Logical Instructions These instructions include logical OR, EOR, AND, and NOT as shown in Table 10.7. • Consider AND. B # $8 F, DO . If prior to execution of this instruction, [DO.B] = $72, then after execution of AND. B # $ 8 F, D0, the following result is obtained: Z = 0 […]
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68000 Delay Routine
10.7 68000 Delay Routine Typical 68000 software delay l00ps can be written using MOVE and DBF instructions. For example, the following instruction sequence can be used for a delay l00p of 2 millisecond: Note that DBF.W in the above decrements D0 .W by one, and if DO.W "’ -1 branches to DELAY; ifDO.W = -1, […]
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Example on 68000 programming part 1
Example 10.1 Determine the effect of each of the following 68000 instructions: CLR D0 MOVE. L D1, D0 CLR.L (A0) + MOVE -(A0), D0 MOVE 20 (A0 ), D0 MOVEQ.L #$D7, D0 MOVE 21 (A0, Al.L), D0 Assume the following initial configuration before each instruction is executed; also assume all numbers in hex: Example 10.2 […]
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