Question

POWER KE TRAIL RUN LEARN 1 LEARN FITNESS TEST PULSE DRIVEN CANYON BURE GORGE TRAIL TRAINING ZONES FAT BURN ENDURANCE PERFORMANCE WARM UP / COOL DOWN INCLINE SEGMENT TIME DISTANCE HEART RATE SPEED TIME LAPS CALORES PACE PROGRAM CONTROL ENTER AGE ENTER WEIGHT if SELECT PROGRAM START PROGRAM RECORD 1-STEP INCLINE (grade) 1 2 3 4 5 6 7 8 9 10 1-STEP SPEED (mph) 1 2 3 4 5 6 o 8 10 A WARNING START STOP There are OV POWER A (Yes, it's a very old treadmill. It still works, so it sticks around.) As you can see, there are 20+ buttons and 16 seven-segment displays. Additionally, there are multiple motor controllers, a heart rate sensor, and the safety sensor to make sure that the belt stops if you fall off. Assume that you are writing the code for the microcontroller in this system. Would you use interrupts, polling, or DMA to synchronize the I/O? Justify your answer.

Answer 1

Polling is a procedure written in software that detects that an event has occurred. In this we write a programme to check whether some part of computation needs a attention, because of this lots of cycles may get wasted.

In interrupt it there is a command that takes the CPU to the required memory location to perform the task, so it doesn't require attention and unwanted cycle loss may be skipped.

DMA is a hardware process that can handle data transfers without processor intervention. Thus, events can happen behind the scene without needing to interrupt the processor. DMA is best suited (but not limited to) mass data transfers, from peripheral to memory, memory to peripheral, or memory to memory. A typical example of DMA data transfer is high-speed ADC sampling, video recording and playback, or audio recording and playback.

So here we want to track the heart rate, motion sensor and so on. To tackle this problem polling is not the best option as it has cycle loss, then interrupt is quit great for this but DMA gives better functionality and supports mass data calculation. So if DMA based microcontroller is cheap then we will go for DMA but if the cost of interrupt based microcontrollers is low then we have to use interrupt, yes cost of component affects the profit of company.