El E 485 Test 3 Fall 1999
This in an Engineering School Honor Code assignment.
References Section: The following references are allowed if they do not have
any “illegal” information—the A86/D86 reference manual, handout on 8088
instructions, handout on 8255 and 8253 control words, handout on 8255 modes.
1) (30 points)
Assume that:
the procedure Get_AD will sample the A/D channel whose number is stored
in the AL register and return with an 8-bit number in the AL register. A/D
inputs are calibrated with an LSB of 10 millivolts.
the procedure Send_DA will output a voltage on the D/A channel whose
number is stored in the AL register. The voltage output is proportional to
the number stored in the AH register, and is calibrated with an LSB of 20
millivolts.
the procedure StepTime will delay for the number of milliseconds stored in the
DX register
the black box shown has two analog voltage outputs, DeltaV and Vmax.
Write a commented 8088 assembly language procedure, Sawtooth, that will
create 5,000 cycles of a sawtooth function as shown below on D/A channel 1.
The step size is determined by DeltaV from the black box and the amplitude
is limited by Vmax from the black box. The duration of each step should be
about 1 millisecond.
Vmax
DeltaV
A/D Channel 3
A/D Channel 6
0
Vmax
DeltaV
