Lecture 16

Question 1

What is a Timer/counter

Answer 1

A register that counts up (or down) with every transition on an input signal

Question 2

Option 1 Input signal is a Periodic signal with known frequency

Answer 2

Count register can be used for time-keeping or performing actions with controlled timing.

Question 3

Option 2: Input signal is an external signal without known timing

Answer 3

Count register can be used to count number of pulses on input signal.

Question 4

The 2 ways the Auto-reload value is used.

Answer 4

1. Counter from ARV - resets back when overflows
   From Zero, resets when hits ARV
   Interrupt generated every iteration.

Question 5

Set-up of timer/counter module is through memory mapped registers

Answer 5

1. Counter/timer clock source selection
2. up/down direction
3. Prescale value
4. Auto-reload value
5. Interrupt enable

Question 6

What is the count register latched to when an external event occurs

Answer 6

The Capture register

Question 7

What can the input capture be used to measure

Answer 7

The leading (or trailing) edges in external signal

Question 8

In output compare mode, the counter register value is continuously compared to what?

Answer 8

The Capture/Compare Register (CCR)

Question 9

Timers with 32-bit timer modules (2)

Answer 9

TIM2

TIM5

Question 10

Timers with 16-bit timer moduels (6)

Answer 10

TIM1
TIM3
TIM4
TIM9
TIM10
TIM11

Question 11

What bit timer is the SysTick timer

Answer 11

24-bit downcounter with autoreload

Question 12

Timers - in Slave mode.

Reset

Answer 12

Register is reinitialized on trigger input

Question 13

Timers - in Slave mode.

Gated

Answer 13

timer/counter is enabled depending on level of selected input

Question 14

Timers - in Slave mode.

Triggered

Answer 14

Timer/counter starts in response to event on selected input

Question 15

What is a Watchdog TImer (WDT)

Answer 15

A hardware timer that automatically generates a system reset if the main program neglects to periodically service it.