TIMER Registers

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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[edit]

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[edit]

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[edit]

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[edit]

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