70 строки
1,9 КиБ
Go
70 строки
1,9 КиБ
Go
//go:build rp2040
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package machine
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import (
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"device/rp"
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)
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// Watchdog provides access to the hardware watchdog available
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// in the RP2040.
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var Watchdog = &watchdogImpl{}
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const (
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// WatchdogMaxTimeout in milliseconds (approx 8.3s).
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//
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// Nominal 1us per watchdog tick, 24-bit counter,
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// but due to errata two ticks consumed per 1us.
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// See: Errata RP2040-E1
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WatchdogMaxTimeout = (rp.WATCHDOG_LOAD_LOAD_Msk / 1000) / 2
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)
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type watchdogImpl struct {
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// The value to reset the counter to on each Update
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loadValue uint32
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}
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// Configure the watchdog.
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//
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// This method should not be called after the watchdog is started and on
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// some platforms attempting to reconfigure after starting the watchdog
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// is explicitly forbidden / will not work.
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func (wd *watchdogImpl) Configure(config WatchdogConfig) error {
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// x2 due to errata RP2040-E1
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wd.loadValue = config.TimeoutMillis * 1000 * 2
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if wd.loadValue > rp.WATCHDOG_LOAD_LOAD_Msk {
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wd.loadValue = rp.WATCHDOG_LOAD_LOAD_Msk
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}
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rp.WATCHDOG.CTRL.ClearBits(rp.WATCHDOG_CTRL_ENABLE)
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// Reset everything apart from ROSC and XOSC
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rp.PSM.WDSEL.Set(0x0001ffff &^ (rp.PSM_WDSEL_ROSC | rp.PSM_WDSEL_XOSC))
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// Pause watchdog during debug
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rp.WATCHDOG.CTRL.SetBits(rp.WATCHDOG_CTRL_PAUSE_DBG0 | rp.WATCHDOG_CTRL_PAUSE_DBG1 | rp.WATCHDOG_CTRL_PAUSE_JTAG)
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// Load initial counter
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rp.WATCHDOG.LOAD.Set(wd.loadValue)
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return nil
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}
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// Starts the watchdog.
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func (wd *watchdogImpl) Start() error {
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rp.WATCHDOG.CTRL.SetBits(rp.WATCHDOG_CTRL_ENABLE)
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return nil
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}
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// Update the watchdog, indicating that the app is healthy.
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func (wd *watchdogImpl) Update() {
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rp.WATCHDOG.LOAD.Set(wd.loadValue)
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}
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// startTick starts the watchdog tick.
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// cycles needs to be a divider that when applied to the xosc input,
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// produces a 1MHz clock. So if the xosc frequency is 12MHz,
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// this will need to be 12.
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func (wd *watchdogImpl) startTick(cycles uint32) {
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rp.WATCHDOG.TICK.Set(cycles | rp.WATCHDOG_TICK_ENABLE)
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}
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