Low level 32u4 Timers are complicated. Here is a sample Arduino program that configures the three usable Timers when using the Arduino platform.
The starting timer value...
TCNT# = <0 ~ 2^16 - 1>
To enable or disable a timer1 and timer3...
| Timer State | TIMSK# |
|---|---|
| STOP | 0x0 |
| START | 0x1 |
To configure the prescaler for the timer1 and timer3...
| Prescaler | TCCR#B |
|---|---|
| STOP | 0x0 |
| CLK / 1 | 0x1 |
| CLK / 8 | 0x2 |
| CLK / 64 | 0x3 |
| CLK / 256 | 0x4 |
| CLK / 1024 | 0x5 |
Set the starting timer value...
TCNT# = <0 ~ 2^8 - 1>
Note: Additional settings can enable 10-bit mode
To enable or disable a timer...
| Timer State | TIMSK# |
|---|---|
| STOP | 0x0 |
| START | (1<<TOIE4) |
To configure the prescaler for the timer...
| Prescaler | TCCR#B |
|---|---|
| STOP | 0x0 |
| CLK / 1 | 0x1 |
| CLK / 2 | 0x2 |
| CLK / 4 | 0x3 |
| CLK / 8 | 0x4 |
| CLK / 16 | 0x5 |
| CLK / 32 | 0x6 |
| CLK / 64 | 0x7 |
| CLK / 128 | 0x8 |
| CLK / 256 | 0x9 |
| CLK / 512 | 0xA |
| CLK / 1024 | 0xB |
| CLK / 2048 | 0xC |
| CLK / 4096 | 0xD |
| CLK / 8192 | 0xE |
| CLK / 16384 | 0xF |
All source code in Timer32u4 is released under the MIT license. See LICENSE for details.