Midterm Examination Solutions Fall 2004

PwnHero QUESTIONS 1. Enter the ASSEMBLY LANGUAGE instructions in the chart below that corresponds to the comments in the chart. Remember to start your program at HEX Address 6000. Address Label Operation Operand Comments Reserve four bytes starting at address 0000 Starting address of the program Initialize the ADCTL register to perform 4 conversions from E0 and stop Start A/D conversion Check if conversion is complete Wait until the conversion is complete Save the first result of the conversion to HEX address 0065 in Direct Mode Stop execution of the program What is the corresponding voltage for E0, if the content of address 0065 is 64? 2. What is the content of the memory location result? Prove your answer. org $00 result rmb 1 org $6000 ldx #array ldaa #8 bsr subr stab result swi subr psha clrb again addb 0,x inx deca bne again pula lsra div lsrb lsra bne div rts array fcb 3, 5, 1, 7, 2, 4, 1, 1 end 3. Write a program that writes a letter ‘H’ into LCD data register (address $1401) every time the voltage level of IRQ pin goes low. Assume the voltage level of the IRQ pin returns to high before the IRQ service is exited. (Note: IRQ interrupt pseudo vector is $00EE). PwnHero.com