TIMER Registers

There are 4 timers. These timers run at a frequency of 67,027,964.0 ± 2^-32 Hz (i.e. exactly half the ARM9 clock frequency).

Registers

Old3DS	Name	Address	Width	Used by
Yes	TIMER_VAL(n)	0x10003000 + 4*n	2	Boot9, Kernel9
Yes	TIMER_CNT(n)	0x10003002 + 4*n	2	Boot9, Kernel9

TIMER_VAL

Writing to TIMER_VAL loads a starting value for one of the 4 timers, while reading it will show the current timer value.

TIMER_CNT

Bit	Description
1-0	Prescaler select (0=F/1, 1=F/64, 2=F/256, 3=F/1024)
2	Count-up (0=Disabled, 1=Enabled)
5-3	Not used
6	IRQ enable (0=Disabled, 1=IRQ on timer value overflow)
7	Start/Stop (0=Stop, 1=Start)

Count-up

When count-up is enabled, the timer value will increase every time the previous timer overflows.