TIMER Registers: Difference between revisions
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Kernel9 treats F/64 as (ARM 9 clockrate)/128 |
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There are 4 timers. These timers run at a frequency of 67,027,964.0 ± 2<sup>-32</sup> Hz (i.e. exactly half the ARM9 clock frequency). | |||
= Registers = | |||
{| class="wikitable" border="1" | {| class="wikitable" border="1" | ||
! | ! Old3DS | ||
! | ! Name | ||
! | ! Address | ||
! Width | |||
! Used by | |||
|- | |- | ||
| | | style="background: green" | Yes | ||
| | | [[#TIMER_VAL|TIMER_VAL]](n) | ||
| 0x10003000 + 4*n | |||
| 2 | | 2 | ||
| Boot9, Kernel9 | |||
|- | |- | ||
| | | style="background: green" | Yes | ||
| | | [[#TIMER_CNT|TIMER_CNT]](n) | ||
| 0x10003002 + 4*n | |||
| 2 | | 2 | ||
| Boot9, Kernel9 | |||
|} | |} | ||
= | == TIMER_VAL == | ||
Writing to | 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 == | ||
{| class="wikitable" border="1" | {| class="wikitable" border="1" | ||
! Bit | |||
! | ! Description | ||
! | |||
|- | |- | ||
| 0 | | 1-0 | ||
| Prescaler select (0=F/1, 1=F/64, 2=F/256, 3=F/1024) | | Prescaler select (0=F/1, 1=F/64, 2=F/256, 3=F/1024) | ||
|- | |- | ||
| Line 53: | Line 36: | ||
| Count-up (0=Disabled, 1=Enabled) | | Count-up (0=Disabled, 1=Enabled) | ||
|- | |- | ||
| 3 | | 5-3 | ||
| Not used | | Not used | ||
|- | |- | ||
| Line 63: | Line 46: | ||
|} | |} | ||
= Count-up = | == Count-up == | ||
When count-up is enabled, the timer value will increase every time the previous timer overflows. | When count-up is enabled, the timer value will increase every time the previous timer overflows. | ||
Latest revision as of 22:00, 15 February 2017
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.