Difference between revisions of "TIMER Registers"
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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 | |
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|- | |- | ||
| − | | | + | | 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 52: | Line 36: | ||
| Count-up (0=Disabled, 1=Enabled) | | Count-up (0=Disabled, 1=Enabled) | ||
|- | |- | ||
| − | | 3 | + | | 5-3 |
| Not used | | Not used | ||
|- | |- | ||
| Line 62: | 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 21:00, 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[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.